adventofcode/2015/day03/day03.c

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#include <stdio.h>
void part1() {
printf("Part 1\n");
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char ch = getchar();
int visits[1000][1000];
for(int i = 0; i < 1000; i++) {
for(int j = 0; j < 1000; j++) {
visits[i][j] = 0;
}
}
int x = 0, y = 0, minx = 0, maxx = 0, miny = 0, maxy = 0;
int inc = 0;
while(ch) {
visits[x+500][y+500]++;
if(ch == '\n') { break; }
switch(ch) {
case '>':
x++;
break;
case 'v':
y--;
break;
case '<':
x--;
break;
case '^':
y++;
break;
}
if(x > maxx) {
maxx = x;
}
if(x < minx) {
minx = x;
}
if(y > maxy) {
maxy = y;
}
if(y < miny) {
miny = y;
}
ch = getchar();
}
int result = 0;
for(int i = 0; i < 1000; i++) {
for(int j = 0; j < 1000; j++) {
if(visits[i][j] > 0) {
result++;
}
}
}
printf("%d houses\n", result);
}
void part2() {
printf("Part 2\n");
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char ch = getchar();
int visits[1000][1000];
for(int i = 0; i < 1000; i++) {
for(int j = 0; j < 1000; j++) {
visits[i][j] = 0;
}
}
int x1 = 0, y1 = 0, x2 = 0, y2 = 0, minx = 0, maxx = 0, miny = 0, maxy = 0;
int inc = 0;
int robo = -1;
int lastOutLngth = 0;
while(ch) {
robo++;
int usex = x1, usey = y1;
if(robo % 2 == 1) {
usex = x2;
usey = y2;
}
visits[usex+500][usey+500]++;
if(ch == '\n') { break; }
switch(ch) {
case '>':
usex++;
break;
case 'v':
usey--;
break;
case '<':
usex--;
break;
case '^':
usey++;
break;
}
if(usex > maxx) {
maxx = usex;
}
if(usex < minx) {
minx = usex;
}
if(usey > maxy) {
maxy = usey;
}
if(usey < miny) {
miny = usey;
}
// Get the next char
if(robo % 2 == 1) {
x2 = usex;
y2 = usey;
} else {
x1 = usex;
y1 = usey;
}
ch = getchar();
}
// Now find how many houses got presents
int result = 0;
for(int i = 0; i < 1000; i++) {
for(int j = 0; j < 1000; j++) {
if(visits[i][j] > 0) {
result++;
}
}
}
printf("%d houses\n", result);
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}
int main(int argc, char **argv) {
int doPart = 1;
if(argc > 1) { doPart = argv[1][0] - '0'; }
if(doPart == 1) {
part1();
} else {
part2();
}
return 0;
}