求1-9的全排列
牛客网-数字1-9的全排列
#define N 9
int x[N];
int counts = 0;
void dump() {
int i = 0;
for (i = 0; i < N; i++) {
printf("%d", x[i]);
}
printf("\n");
}
void swap(int a, int b) {
int t = x[a];
x[a] = x[b];
x[b] = t;
}
void run(int n) {
int i;
if (N - 1 == n) {
dump();
counts++;
return;
}
for (i = n; i < N; i++) {
swap(n, i);
run(n + 1);
swap(n, i);
}
}
int main() {
int i;
for (i = 0; i < N; i++) {
x[i] = i + 1;
}
run(0);
printf("* Total: %d\n", counts);
}
