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| #include <stdio.h>
int map[5][5];
struct people{
int y;
int x;
int collect;
};
int dx[4] = {0,1,0,-1};
int dy[4] = {-1,0,1,0};
int ans = 0, apples = 25;
void DFS(people &a, people &b){
if(a.x == b.x && a.y == b.y){
if(a.collect + b.collect == apples + 1)
++ans;
return;
}
people na, nb;
for(int i = 0; i < 4; ++i) {
na.x = a.x + dx[i];
na.y = a.y + dy[i];
if(0<=na.x && na.x < 5 && 0<=na.y && na.y < 5 && !map[na.y][na.x]) {
for (int j = 0; j < 4; ++j) {
nb.x = b.x + dx[j];
nb.y = b.y + dy[j];
if(0<=nb.x && nb.x < 5 && 0<=nb.y && nb.y < 5 && !map[nb.y][nb.x]){
map[na.y][na.x] = map[nb.y][nb.x] = 1;
na.collect = a.collect + 1;
nb.collect = b.collect + 1;
DFS(na,nb);
map[na.y][na.x] = map[nb.y][nb.x] = 0;
}
}
}
}
}
int main(void) {
int N,x,y;
scanf("%d",&N);
apples -= N;
for(int i = 0; i < N; ++i) {
scanf("%d %d", &y, &x);
map[y-1][x-1] = 1;
}
people a, b;
a.x = a.y = 0;
a.collect = b.collect = 1;
b. x = b.y = 4;
map[0][0] = map[4][4] = 1;
DFS(a,b);
printf("%d",ans);
return 0;
}
|
