Day10

day10/c/day10.c

@@ -0,0 +1,102 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+#define MAX_DIMENSION 128
+
+int get_trails(char**, int, int, int, int, int**);
+
+int main() {
+    char c;
+
+    char **map = calloc(MAX_DIMENSION, sizeof(map[0]));
+
+    int rows = 0, i = 0, columns;
+    map[rows] = calloc(MAX_DIMENSION, sizeof(map[0][0]));
+
+    while ((c = getchar()) != EOF) {
+        map[rows][i] = c;
+        i++;
+        if (c != '\n') {
+            continue;
+        }
+
+        columns = i - 1;
+        rows++;
+        i = 0;
+        map[rows] = calloc(MAX_DIMENSION, sizeof(map[0][0]));
+    }
+
+    int **reachable = calloc(rows, sizeof(reachable[0]));
+    for (i = 0; i < rows; i++) {
+        reachable[i] = calloc(columns, sizeof(reachable[0][0]));
+    }
+
+    int score = 0;
+    int rating = 0;
+    // For each '0'
+    for (i = 0; i < rows; i++) {
+        for (int j = 0; j < columns; j++) {
+            if (map[i][j] != '0') {
+                continue;
+            }
+
+            rating += get_trails(map, rows, columns, i, j, reachable);
+            // Count reachable
+            for (int k = 0; k < rows; k++) {
+                for (int l = 0; l < columns; l++) {
+                    score += reachable[k][l];
+                    reachable[k][l] = 0;
+                }
+            }
+        }
+    }
+
+    for (i = 0; i < rows; i++) {
+        free(reachable[i]);
+    }
+    free(reachable);
+    for (i = 0; i < rows + 1; i++) {
+        free(map[i]);
+    }
+    free(map);
+
+    printf("%i\n", score);
+    printf("%i\n", rating);
+}
+
+int get_trails(char** map, int rows, int columns, int row, int column, int** reachable) {
+    if (map[row][column] == '9') {
+        reachable[row][column] = 1;
+        return 1;
+    }
+
+    int x, y;
+    char next = map[row][column] + 1;
+    int trails = 0;
+    // up
+    x = row - 1;
+    y = column;
+    if (x >= 0 && map[x][y] == next) {
+        trails += get_trails(map, rows, columns, x, y, reachable);
+    }
+    // down
+    x = row + 1;
+    y = column;
+    if (x < rows && map[x][y] == next) {
+        trails += get_trails(map, rows, columns, x, y, reachable);
+    }
+    // left
+    x = row;
+    y = column + 1;
+    if (y < columns && map[x][y] == next) {
+        trails += get_trails(map, rows, columns, x, y, reachable);
+    }
+    // right
+    x = row;
+    y = column - 1;
+    if (y >= 0 && map[x][y] == next) {
+        trails += get_trails(map, rows, columns, x, y, reachable);
+    }
+
+    return trails;
+}

day10/input.txt

@@ -0,0 +1,54 @@
+212521982345455432198898732343201001454321076767899872
+101430671156766718089087001432102122367410789898721701
+234549560049859809670106126549893432198523650127630652
+345678432132343218543215437456784543007694540134544543
+434989010101034567894326458941089656912784343296531014
+123968523218954326287478947032178767843895256787432543
+037879654305869210156565432142189626756706101208956632
+010968760456778981432101943443076212389617890312347701
+323459821678765476583201875654561003476526345423698801
+011234734569012345694112766743432876565430256784510932
+010345654554212014785073450898101986676321100898929841
+143456703623103423456787321287632987685672901289838750
+212769812514398512987896544379443456894589874356745669
+301898453405487600121095434568543670123601065105210178
+498782345654676321436784323877612589010892110234312321
+567101908723521030545654012981003438756763323987603430
+323877819810437841690343021542312321065654332109544543
+014966521923456956781252120455401487654505445678037652
+565455430810398105898763214345566590123218764789128781
+678321876760567234237454905216697687689439653234569390
+549050945651456340145667876107788014578321342106778434
+432167834512301254206758989038979123065430211067884521
+212058723003456763219843210123460132104321203458990690
+103449012124567895430764505674321043895650432143021788
+214530101013098986721256034985452344786766501032134659
+345621232322121234890340125676965435689897865401235678
+238789985421030345234543234767876105476101974321945234
+129376576534781676167652149866765256785232389450876165
+023403456215696787018967019875454343494341071265210074
+016512567304345698101278112562343852014556780374391189
+187876458412234598790349603401438961025698895489580543
+098962389561103347685456784876547873234767216785671672
+123451049870101256576545692910687210189854306894502981
+212945432943232345677834501431296332182344345663213870
+301876501854569431988925232321345345091103216756344561
+676510345763078520123810123410543456780234109865432150
+783401256762107019654320294567632109876542106776843001
+892313879856234198734521287678932323438943769089987612
+341054965447895287645632789456541010567659858123656543
+250123832332196014532745610367692101298365647654567698
+167814001541087123691821001298789854303234737843238787
+078905123456789234780934789656730763214159826943129898
+980876432965410165690695678749821278934067015652010789
+801986501874321074321783265637832123653458234761001656
+212567988965010787210654104521945034562109101891012347
+123498677654321298323545003010876453078045610123456798
+034014576103432186789276512123289342199236769032347810
+145623985412545085652189467898100256787100898741016921
+898767234307696198543011056967221105107231239653455430
+745678101268987585654322343254339012218774381012768741
+234989089456789676789113698107448763329783498019889650
+101345674301410566541004567898758954458692567325676341
+013216765210323455632123476127667763067501101234765432
+322109876323454556789012981034554892155432101289876501

day10/sample.txt

@@ -0,0 +1,4 @@
+0123
+1234
+8765
+9876

day10/sample2.txt

@@ -0,0 +1,7 @@
+...0...
+...1...
+...2...
+6543456
+7.....7
+8.....8
+9.....9

day10/sample3.txt

@@ -0,0 +1,7 @@
+..90..9
+...1.98
+...2..7
+6543456
+765.987
+876....
+987....

day10/sample4.txt

@@ -0,0 +1,7 @@
+10..9..
+2...8..
+3...7..
+4567654
+...8..3
+...9..2
+.....01

day10/samplee.txt

@@ -0,0 +1,8 @@
+89010123
+78121874
+87430965
+96549874
+45678903
+32019012
+01329801
+10456732