diff --git a/input/day5.txt b/input/day5.txt
new file mode 100644
index 0000000..c666051
--- /dev/null
+++ b/input/day5.txt
@@ -0,0 +1,500 @@
+405,945 -> 780,945
+253,100 -> 954,801
+518,300 -> 870,300
+775,848 -> 20,848
+586,671 -> 469,671
+598,20 -> 900,20
+51,975 -> 438,588
+561,456 -> 67,456
+353,135 -> 882,664
+357,873 -> 407,873
+480,247 -> 774,247
+230,895 -> 230,709
+590,738 -> 644,792
+696,821 -> 696,198
+501,461 -> 85,461
+884,88 -> 884,922
+140,780 -> 146,780
+795,208 -> 273,208
+256,185 -> 256,525
+282,196 -> 282,85
+701,133 -> 18,133
+623,548 -> 623,573
+734,895 -> 29,190
+212,944 -> 934,944
+948,504 -> 948,502
+551,613 -> 551,27
+62,54 -> 452,54
+915,851 -> 915,290
+924,843 -> 924,145
+662,412 -> 422,172
+465,87 -> 247,87
+391,91 -> 326,91
+267,572 -> 267,306
+84,505 -> 594,505
+453,383 -> 80,10
+737,891 -> 784,891
+599,339 -> 40,898
+868,962 -> 31,125
+153,661 -> 705,661
+760,74 -> 339,495
+972,72 -> 972,714
+579,636 -> 169,226
+365,218 -> 118,465
+128,906 -> 767,267
+733,165 -> 121,165
+877,99 -> 105,871
+176,917 -> 754,917
+14,14 -> 981,981
+170,958 -> 170,859
+861,25 -> 96,790
+128,143 -> 128,49
+874,367 -> 334,367
+373,434 -> 373,747
+799,946 -> 439,586
+17,923 -> 814,126
+734,192 -> 734,632
+267,280 -> 877,890
+457,500 -> 457,26
+525,679 -> 525,22
+985,64 -> 85,964
+312,411 -> 312,287
+554,860 -> 600,860
+209,163 -> 628,163
+47,30 -> 917,900
+870,948 -> 625,703
+965,980 -> 53,68
+874,631 -> 874,41
+770,29 -> 770,882
+950,988 -> 411,449
+766,900 -> 904,900
+77,23 -> 923,869
+528,151 -> 528,96
+785,468 -> 218,468
+150,932 -> 333,932
+908,846 -> 654,846
+467,220 -> 588,220
+303,437 -> 219,437
+617,71 -> 899,353
+116,311 -> 116,816
+251,165 -> 316,165
+126,897 -> 854,169
+254,473 -> 818,473
+817,265 -> 98,984
+660,492 -> 558,492
+562,117 -> 64,615
+857,808 -> 857,311
+39,641 -> 39,703
+256,981 -> 988,249
+923,175 -> 923,902
+372,800 -> 503,800
+48,339 -> 48,156
+852,476 -> 852,397
+874,190 -> 248,816
+509,629 -> 503,629
+246,17 -> 246,341
+903,961 -> 568,626
+405,740 -> 975,740
+25,10 -> 982,967
+761,287 -> 254,794
+21,514 -> 21,111
+772,350 -> 219,903
+61,56 -> 275,270
+608,197 -> 608,719
+275,30 -> 275,145
+712,601 -> 850,739
+173,205 -> 173,667
+93,644 -> 519,218
+60,48 -> 911,899
+21,975 -> 980,16
+333,602 -> 634,602
+899,374 -> 96,374
+283,209 -> 963,889
+22,20 -> 987,985
+494,66 -> 70,490
+836,876 -> 37,77
+151,530 -> 472,851
+459,531 -> 127,199
+564,489 -> 315,240
+193,341 -> 361,341
+639,680 -> 511,680
+855,217 -> 855,352
+88,909 -> 920,77
+948,318 -> 452,814
+957,967 -> 957,297
+741,172 -> 140,773
+785,528 -> 467,528
+135,658 -> 458,658
+821,653 -> 821,633
+932,137 -> 415,137
+858,638 -> 858,696
+494,495 -> 649,495
+586,261 -> 478,369
+18,680 -> 571,680
+872,233 -> 872,823
+715,935 -> 861,935
+85,251 -> 206,372
+42,972 -> 940,74
+587,955 -> 66,955
+393,466 -> 771,466
+759,744 -> 36,21
+694,90 -> 195,589
+210,456 -> 857,456
+656,476 -> 177,955
+391,224 -> 902,735
+929,802 -> 69,802
+548,395 -> 892,395
+576,838 -> 671,838
+402,412 -> 899,412
+567,601 -> 800,834
+106,386 -> 907,386
+848,349 -> 848,869
+209,392 -> 785,392
+28,105 -> 853,930
+395,432 -> 795,432
+582,570 -> 582,514
+48,410 -> 211,573
+248,617 -> 248,848
+695,174 -> 941,420
+215,651 -> 215,124
+419,555 -> 112,555
+358,975 -> 169,975
+732,247 -> 732,573
+132,983 -> 132,845
+476,110 -> 476,196
+852,437 -> 640,437
+973,42 -> 109,906
+954,797 -> 337,180
+544,233 -> 134,233
+412,150 -> 93,150
+140,296 -> 140,407
+485,875 -> 395,875
+600,942 -> 931,942
+235,677 -> 235,431
+841,745 -> 148,52
+265,803 -> 265,140
+369,597 -> 230,736
+788,745 -> 788,422
+29,677 -> 75,677
+590,669 -> 590,638
+24,23 -> 24,438
+279,476 -> 770,967
+342,186 -> 57,186
+50,49 -> 350,349
+968,40 -> 28,980
+101,101 -> 978,101
+897,48 -> 27,918
+595,232 -> 595,211
+813,982 -> 335,504
+624,41 -> 261,41
+743,102 -> 530,102
+234,814 -> 234,527
+597,242 -> 492,242
+36,84 -> 339,84
+685,729 -> 398,729
+506,733 -> 506,150
+140,788 -> 816,112
+775,816 -> 316,357
+934,394 -> 301,394
+635,983 -> 750,983
+128,29 -> 128,712
+347,348 -> 724,725
+836,367 -> 390,367
+60,718 -> 620,718
+476,786 -> 476,870
+318,490 -> 192,490
+736,608 -> 736,926
+14,79 -> 14,777
+913,245 -> 344,814
+876,775 -> 72,775
+109,273 -> 109,416
+376,64 -> 376,592
+988,11 -> 22,977
+544,602 -> 453,602
+703,585 -> 703,602
+147,976 -> 147,512
+887,681 -> 657,451
+36,913 -> 36,321
+184,723 -> 252,655
+523,905 -> 523,610
+626,106 -> 653,106
+703,211 -> 703,376
+770,175 -> 770,765
+387,628 -> 233,628
+69,890 -> 877,82
+608,751 -> 699,751
+379,958 -> 572,958
+556,555 -> 276,835
+890,681 -> 234,25
+937,792 -> 589,444
+842,296 -> 547,296
+488,638 -> 488,434
+455,823 -> 484,823
+488,610 -> 488,948
+58,829 -> 931,829
+453,481 -> 17,917
+629,473 -> 629,53
+584,512 -> 345,512
+150,92 -> 283,92
+663,692 -> 911,692
+243,835 -> 243,600
+28,26 -> 987,985
+422,388 -> 385,388
+534,798 -> 736,798
+635,394 -> 799,394
+155,895 -> 82,968
+124,926 -> 968,82
+142,431 -> 645,934
+201,977 -> 601,977
+169,322 -> 775,322
+207,251 -> 652,696
+989,975 -> 25,11
+131,89 -> 131,864
+981,989 -> 100,108
+114,84 -> 114,434
+98,713 -> 689,713
+944,262 -> 548,262
+481,568 -> 481,904
+734,883 -> 734,605
+716,687 -> 737,666
+228,155 -> 702,155
+847,675 -> 896,675
+33,121 -> 33,865
+58,211 -> 134,211
+577,154 -> 659,236
+415,958 -> 504,958
+984,359 -> 55,359
+215,22 -> 357,22
+518,232 -> 406,232
+264,950 -> 264,672
+891,549 -> 891,45
+785,328 -> 498,328
+496,815 -> 664,815
+138,55 -> 406,55
+38,823 -> 38,383
+467,184 -> 553,98
+248,794 -> 864,178
+415,561 -> 415,148
+665,726 -> 665,236
+767,777 -> 547,777
+453,860 -> 453,196
+23,645 -> 755,645
+611,985 -> 559,985
+33,978 -> 952,59
+772,36 -> 889,36
+626,521 -> 781,521
+722,502 -> 722,30
+978,946 -> 174,142
+224,901 -> 655,470
+924,142 -> 135,931
+505,171 -> 365,171
+303,888 -> 663,888
+716,838 -> 255,377
+494,390 -> 563,459
+213,595 -> 516,595
+264,436 -> 921,436
+785,749 -> 785,78
+50,50 -> 979,979
+96,72 -> 96,564
+647,278 -> 647,460
+452,656 -> 452,487
+686,145 -> 78,753
+900,973 -> 728,973
+545,137 -> 572,164
+245,211 -> 726,211
+550,606 -> 550,41
+447,25 -> 447,197
+941,581 -> 597,581
+299,486 -> 484,486
+789,67 -> 55,801
+489,842 -> 489,228
+716,452 -> 627,452
+114,735 -> 329,950
+810,157 -> 905,157
+575,397 -> 568,404
+414,221 -> 779,221
+698,363 -> 745,363
+976,498 -> 271,498
+186,324 -> 519,324
+105,777 -> 105,491
+241,58 -> 241,102
+126,883 -> 894,115
+890,853 -> 731,694
+760,713 -> 735,713
+309,409 -> 61,161
+365,263 -> 365,763
+425,591 -> 623,591
+224,233 -> 645,233
+669,872 -> 669,594
+112,773 -> 718,167
+966,168 -> 966,223
+982,527 -> 982,40
+439,688 -> 668,688
+537,685 -> 357,685
+607,164 -> 127,164
+192,894 -> 192,987
+130,196 -> 130,311
+847,987 -> 847,708
+354,66 -> 354,260
+660,441 -> 983,441
+868,282 -> 868,962
+915,272 -> 239,948
+960,970 -> 26,36
+595,837 -> 11,253
+258,533 -> 258,209
+664,802 -> 664,948
+683,117 -> 448,117
+961,104 -> 961,231
+517,427 -> 134,427
+233,451 -> 853,451
+978,412 -> 978,496
+222,71 -> 794,71
+80,343 -> 604,867
+209,104 -> 987,882
+271,232 -> 711,232
+754,329 -> 301,329
+560,937 -> 716,937
+653,194 -> 441,406
+655,506 -> 655,671
+599,336 -> 720,457
+709,895 -> 468,895
+538,432 -> 885,779
+72,231 -> 471,231
+694,131 -> 694,610
+380,37 -> 380,673
+46,921 -> 721,921
+126,823 -> 343,823
+771,617 -> 771,645
+356,734 -> 356,406
+710,504 -> 710,277
+507,65 -> 510,65
+292,913 -> 292,944
+816,640 -> 913,640
+101,132 -> 101,96
+180,21 -> 743,584
+548,231 -> 453,231
+459,248 -> 498,248
+567,637 -> 242,962
+471,418 -> 471,601
+104,822 -> 911,15
+802,583 -> 459,583
+330,681 -> 253,604
+10,431 -> 209,431
+220,776 -> 908,88
+458,508 -> 458,697
+87,803 -> 885,803
+636,372 -> 324,372
+891,528 -> 891,489
+70,274 -> 70,268
+255,587 -> 976,587
+498,69 -> 498,250
+783,838 -> 48,838
+864,344 -> 968,240
+323,734 -> 234,734
+657,347 -> 657,410
+661,682 -> 48,682
+344,815 -> 344,132
+137,878 -> 503,878
+927,975 -> 982,920
+753,964 -> 16,227
+539,957 -> 539,48
+314,651 -> 698,651
+925,653 -> 271,653
+861,518 -> 967,518
+846,126 -> 41,931
+103,409 -> 118,394
+327,185 -> 874,732
+716,930 -> 716,40
+315,702 -> 246,702
+130,377 -> 268,377
+845,978 -> 39,172
+147,977 -> 147,725
+762,660 -> 606,660
+871,186 -> 132,186
+388,320 -> 388,584
+302,410 -> 15,410
+336,234 -> 336,673
+331,208 -> 225,208
+95,565 -> 315,785
+843,563 -> 843,640
+521,378 -> 118,378
+963,17 -> 95,885
+862,487 -> 974,487
+874,402 -> 703,402
+692,689 -> 692,237
+947,635 -> 331,635
+540,417 -> 737,220
+770,161 -> 224,161
+721,831 -> 721,424
+10,411 -> 10,87
+11,985 -> 986,10
+465,972 -> 873,972
+844,753 -> 676,753
+181,27 -> 181,105
+450,675 -> 333,558
+578,286 -> 578,509
+87,363 -> 274,363
+892,119 -> 346,665
+363,331 -> 363,22
+508,424 -> 508,53
+371,145 -> 669,145
+109,761 -> 343,761
+328,804 -> 328,570
+411,741 -> 411,269
+30,139 -> 915,139
+912,736 -> 44,736
+555,884 -> 672,884
+433,427 -> 19,841
+793,796 -> 505,508
+737,554 -> 312,979
+726,231 -> 568,231
+954,479 -> 255,479
+33,365 -> 262,365
+677,608 -> 401,608
+245,620 -> 828,37
+295,274 -> 295,10
+906,106 -> 906,263
+682,719 -> 118,155
+208,859 -> 634,859
+739,103 -> 323,103
+360,142 -> 13,489
+131,553 -> 859,553
+483,308 -> 483,124
+776,720 -> 776,259
+528,327 -> 651,450
+423,223 -> 794,223
+898,698 -> 898,315
+488,824 -> 48,824
+164,971 -> 773,362
+975,850 -> 687,850
+504,810 -> 795,810
+562,281 -> 29,814
+639,574 -> 684,529
+417,800 -> 404,800
+335,844 -> 335,907
+17,41 -> 824,848
+644,220 -> 470,220
+304,944 -> 947,944
+122,807 -> 122,257
+308,553 -> 308,819
+22,672 -> 22,386
+837,675 -> 275,113
+716,650 -> 482,650
+212,350 -> 212,105
+213,594 -> 213,119
+431,375 -> 528,278
+499,741 -> 58,741
+600,291 -> 600,955
+905,205 -> 326,205
+584,152 -> 584,871
+49,153 -> 883,987
+818,822 -> 69,822
+938,286 -> 938,832
+75,380 -> 956,380
+986,424 -> 450,960
+736,470 -> 736,853
+872,988 -> 371,988
+102,203 -> 102,123
+518,338 -> 518,360
+819,263 -> 328,754
+952,242 -> 178,242
diff --git a/src/day5.rs b/src/day5.rs
new file mode 100644
index 0000000..12f6bbc
--- /dev/null
+++ b/src/day5.rs
@@ -0,0 +1,112 @@
+use std::cmp::{max, min};
+use std::collections::HashMap;
+use std::fmt::Debug;
+
+pub fn day5() {
+    // let input = r#"
+    // 0,9 -> 5,9
+    // 8,0 -> 0,8
+    // 9,4 -> 3,4
+    // 2,2 -> 2,1
+    // 7,0 -> 7,4
+    // 6,4 -> 2,0
+    // 0,9 -> 2,9
+    // 3,4 -> 1,4
+    // 0,0 -> 8,8
+    // 5,5 -> 8,2
+    //     "#;
+    let input = include_str!("../input/day5.txt");
+
+    let lines: Vec<Line> = input.trim().lines().map(|s| s.into()).collect();
+
+    dbg!(Line {
+        start: Point { x: 9, y: 7 },
+        end: Point { x: 7, y: 9 },
+    }
+    .points(true));
+
+    for with_diag in vec![false, true] {
+        let mut points: HashMap<Point, i32> = HashMap::new();
+        for l in lines.iter() {
+            for p in l.points(with_diag) {
+                match points.get_mut(&p) {
+                    Some(count) => {
+                        *count += 1;
+                    }
+                    None => {
+                        points.insert(p, 1);
+                    }
+                }
+            }
+        }
+
+        println!(
+            "with_diag: {}, overlapping: {}",
+            with_diag,
+            points.values().filter(|&&c| c > 1).count()
+        );
+    }
+}
+
+#[derive(Clone, Copy, PartialEq, Eq, Hash)]
+struct Point {
+    x: i32,
+    y: i32,
+}
+
+impl Debug for Point {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.write_str(&format!("({}, {})", self.x, self.y))
+    }
+}
+
+impl From<&str> for Point {
+    fn from(s: &str) -> Self {
+        let mut components = s.split(",").map(|s| s.parse::<i32>().unwrap());
+        Self {
+            x: components.next().unwrap(),
+            y: components.next().unwrap(),
+        }
+    }
+}
+
+#[derive(Debug, Clone, Copy, PartialEq)]
+struct Line {
+    start: Point,
+    end: Point,
+}
+
+impl Line {
+    fn is_diag(&self) -> bool {
+        self.start.x != self.end.x && self.start.y != self.end.y
+    }
+
+    fn points(&self, with_diags: bool) -> Vec<Point> {
+        if self.is_diag() && !with_diags {
+            return vec![];
+        }
+        let len = if self.start.x == self.end.x {
+            max(self.start.y, self.end.y) - min(self.start.y, self.end.y)
+        } else {
+            max(self.start.x, self.end.x) - min(self.start.x, self.end.x)
+        };
+        let dx = (self.end.x - self.start.x) / len;
+        let dy = (self.end.y - self.start.y) / len;
+        (0..=len)
+            .map(|i| Point {
+                x: self.start.x + dx * i,
+                y: self.start.y + dy * i,
+            })
+            .collect()
+    }
+}
+
+impl From<&str> for Line {
+    fn from(s: &str) -> Self {
+        let mut parts = s.split_whitespace();
+        let start: Point = parts.next().unwrap().into();
+        parts.next();
+        let end: Point = parts.next().unwrap().into();
+        Self { start, end }
+    }
+}
diff --git a/src/main.rs b/src/main.rs
index 1175b7d..41d3cbb 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -4,7 +4,8 @@ mod day1;
 mod day2;
 mod day3;
 mod day4;
+mod day5;
 
 fn main() {
-    day4::day4();
+    day5::day5();
 }