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38 lines
778 B
38 lines
778 B
#include <bits/stdc++.h>
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using namespace std;
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const int N = 15;
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typedef pair<int, int> PII;
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int n, m;
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int res;
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int dx[] = {-1, 0, 1, 0}; // 上右下左
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int dy[] = {0, 1, 0, -1}; // 上右下左
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int st[N][N];
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void dfs(int x, int y, int cnt) {
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if (x == 1 && y == 1 && cnt == m * n) {
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res++;
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return;
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}
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for (int i = 0; i < 4; i++) {
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int tx = x + dx[i], ty = y + dy[i];
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if (tx == 0 || tx > n || ty == 0 || ty > m) continue;
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if (!st[tx][ty]) {
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st[tx][ty] = 1;
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dfs(tx, ty, cnt + 1);
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st[tx][ty] = 0;
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}
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}
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}
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int main() {
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cin >> n >> m;
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dfs(1, 1, 0);
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printf("%d\n", res);
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return 0;
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} /**
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测试数据：
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3 4
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答案：
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4
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*/ |