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53 lines
1.1 KiB
C++
53 lines
1.1 KiB
C++
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#include <iostream>
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#include <vector>
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using std::cin;
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using std::cout;
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using std::endl;
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const long long mod = 281474976710656;
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int n;
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long long ans;
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char g[505][505];
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void dfs1(int, int, std::vector<int>);
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long long dfs2(int, int, std::vector<int>, int, int, std::vector<int>);
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int main() {
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cin >> n;
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for (int i = 1; i <= n; i++) {
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cin >> g[i] + 1;
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}
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dfs1(1, 1, std::vector<int>());
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cout << ans << endl;
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return 0;
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}
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void dfs1(int x, int y, std::vector<int> s) {
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if (x < 1 || x > n || y < 1 || y > n) return;
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s.push_back(g[x][y] - 'A');
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if (x + y == n + 1) {
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ans = (ans + dfs2(n, n, std::vector<int>(), x, y, s)) % mod;
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return;
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}
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dfs1(x + 1, y, s);
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dfs1(x, y + 1, s);
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}
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long long dfs2(
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int x,
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int y,
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std::vector<int> s,
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int lx,
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int ly,
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std::vector<int> t) {
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if (x < lx || x > n || y < ly || y > n) return 0;
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s.push_back(g[x][y] - 'A');
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long long res = 0;
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if (x == lx && y == ly && s == t) return 1;
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res += dfs2(x - 1, y, s, lx, ly, t);
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res += dfs2(x, y - 1, s, lx, ly, t);
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return res;
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}
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