Uva 116 Unidirectional TSP

来源：互联网发布：优化国土空间开发格局编辑：程序博客网时间：2024/05/22 17:11

典型的动态规划问题，类似于数字三角形的感觉。要求字典序路径。

#include <algorithm>#include <iostream>  #include <cstring>    #include <cstdio>    #include <vector>  #include <queue>  #include <map>    using namespace std;      int v[110][110],dp[110][110],path[110][110];int m,n;int main(){while(scanf("%d%d",&m,&n) == 2){for(int i=1; i<=m; i++)for(int j=1; j<=n; j++)scanf("%d",&v[i][j]);memset(dp, 0x3f, sizeof(dp));for(int i=1; i<=m; i++)dp[i][n] = v[i][n];for(int j=n-1; j>0; j--){for(int i=1; i<=m; i++){int row[3] = {i, i-1, i+1};if(i == 1) row[1] = m;else if(i == m) row[2] = 1;sort(row, row + 3);//!保证字典序for(int k=0; k<3; k++){int tmp = dp[row[k]][j+1] + v[i][j];if(dp[i][j] > tmp){dp[i][j] = tmp;path[i][j] = row[k];//记录路径}}}}int ans = 0x3f3f3f3f,now = 1;for(int i=1; i<=m; i++){if(ans > dp[i][1]){ans = dp[i][1];now = i;}}cout << now;for(int i=path[now][1],j=2; j<=n; i=path[i][j], j++)//打印路径cout << " " << i;cout << endl;cout << ans << endl;}return 0;}

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