53 lines
1.2 KiB
C++
53 lines
1.2 KiB
C++
#include <iostream>
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#include <vector>
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using namespace std;
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const int MAX = INT_MAX >> 1;
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int main(){
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//n <= 15, S是少于15位的二进制
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int n;
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cin >> n;
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//从0开始
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vector<vector<int>> dist(n, vector<int>(n, 0));
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vector<vector<int>> dp(n, vector<int>(1 << n, MAX));//dp[i][S];
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int N = 1 << n; // 2 ^ n;
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for(int i = 0; i < n; i++){
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for(int j = 0; j < n; j++){
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cin >> dist[i][j];
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}
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}
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int start, end;
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cin >> start >> end;
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dp[start][1 << start] = 0;
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//S到过的城市
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//开始操作
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for(int mask = 0; mask < N; mask++){
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for(int j = 0; j < n; j++){
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if(dp[j][mask] == MAX || !(mask & (1 << j))) continue;
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for(int v = 0; v < n; v++){
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if(mask & (1 << v)) continue;
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int new_mask = mask | (1 << v);
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//1001 | 0001 = 1001, 1001 ^ 0001 = 1000
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dp[v][new_mask] = min(dp[v][new_mask], dp[j][mask] + dist[j][v]);
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}
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}
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}
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// 计算最小路径：终点为 end，访问所有城市
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int full_mask = (1 << n) - 1; // 所有城市都被访问
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int cost = dp[end][full_mask];
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if (cost == MAX) {
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cout << "No valid path" << endl; // 没有可行路径
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} else {
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cout << cost << endl;
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}
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return 0;
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}
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/*
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4
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0 10 15 20
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10 0 35 25
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15 35 0 30
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20 25 30 0
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0 3
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*/
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