hdoj 2819 Swap (最大匹配+输出路径)
2017-02-19 00:15
507 查看
题意:
给你一个每位是0或1的矩阵,问你是否可以经过交换行和交换列使矩阵的对角线都为1,如果可以输出交换的方法。
思路:
行和列的匹配,左边是行,右边是列,然后如果行列交点是1,那么就可以匹配,看是否为完美匹配,然后输出怎么交换的。
输出交换的路径:
可以锁定行,来选择列和它匹配,将选择的列移动到和该行形成对角线上是1的位置,比如和第一行匹配的列,就要移动要第一列,第二行的,就到第二列。其实就是对第i行,找一个第i个数是1的列和它匹配,然后看是否是最大匹配!
代码:
Given an N*N matrix with each entry equal to 0 or 1. You can swap any two rows or any two columns. Can you find a way to make all the diagonal entries equal to 1?
InputThere are several test cases in the input. The first line of each test case is an integer N (1 <= N <= 100). Then N lines follow, each contains N numbers (0 or 1), separating by space, indicating the N*N matrix.
OutputFor each test case, the first line contain the number of swaps M. Then M lines follow, whose format is “R a b” or “C a b”, indicating swapping the row a and row b, or swapping the column a and column b. (1 <= a, b <= N). Any correct answer will
be accepted, but M should be more than 1000.
If it is impossible to make all the diagonal entries equal to 1, output only one one containing “-1”.
Sample Input
Sample Output
给你一个每位是0或1的矩阵,问你是否可以经过交换行和交换列使矩阵的对角线都为1,如果可以输出交换的方法。
思路:
行和列的匹配,左边是行,右边是列,然后如果行列交点是1,那么就可以匹配,看是否为完美匹配,然后输出怎么交换的。
输出交换的路径:
可以锁定行,来选择列和它匹配,将选择的列移动到和该行形成对角线上是1的位置,比如和第一行匹配的列,就要移动要第一列,第二行的,就到第二列。其实就是对第i行,找一个第i个数是1的列和它匹配,然后看是否是最大匹配!
代码:
#include<bits/stdc++.h> using namespace std; const int maxn = 105; vector<int> e[maxn]; int n, match[maxn], vis[maxn], ans1[maxn], ans2[maxn]; bool dfs(int x) { for(int i = 0; i < e[x].size(); i++) { int to = e[x][i]; if(!vis[to]) { vis[to] = 1; if(!match[to] || dfs(match[to])) { match[to] = x; return true; } } } return false; } int Hungary() { int res = 0; for(int i = 1; i <= n; i++) { memset(vis, 0, sizeof(vis)); res += dfs(i); } return res; } int main(void) { while(cin >> n) { memset(match, 0, sizeof(match)); for(int i = 1; i < maxn; i++) e[i].clear(); for(int i = 1; i <= n; i++) for(int j = 1; j <= n; j++) { int t; scanf("%d", &t); if(t) e[i].push_back(j); } if(Hungary() != n) puts("-1"); else { int cnt = 0; for(int i = 1; i <= n; i++) { int pos; for(int j = 1; j <= n; j++) if(match[j] == i) { pos = j; break; } if(pos != i) { ans1[cnt] = i; ans2[cnt++] = pos; swap(match[i], match[pos]); } } printf("%d\n", cnt); for(int i = 0; i < cnt; i++) printf("C %d %d\n", ans1[i], ans2[i]); } } return 0; }
Given an N*N matrix with each entry equal to 0 or 1. You can swap any two rows or any two columns. Can you find a way to make all the diagonal entries equal to 1?
InputThere are several test cases in the input. The first line of each test case is an integer N (1 <= N <= 100). Then N lines follow, each contains N numbers (0 or 1), separating by space, indicating the N*N matrix.
OutputFor each test case, the first line contain the number of swaps M. Then M lines follow, whose format is “R a b” or “C a b”, indicating swapping the row a and row b, or swapping the column a and column b. (1 <= a, b <= N). Any correct answer will
be accepted, but M should be more than 1000.
If it is impossible to make all the diagonal entries equal to 1, output only one one containing “-1”.
Sample Input
2 0 1 1 0 2 1 0 1 0
Sample Output
1 R 1 2 -1
相关文章推荐
- hdu 2819 Swap(二分图最大匹配,输出路径)
- HDOJ 2819 - Swap 二分图最大匹配..并输出方法..
- HDU 2819 Swap (最大二分匹配+输出路径)
- HDOJ 题目2189 Swap(二分图最大匹配,输出路径)
- HDU-2819-Swap [二分匹配][输出路径]
- [HDOJ2819]Swap(二分图最大匹配, 匈牙利算法)
- hdu2819 Swap 二分图最大匹配 输出路径
- HDU - 2819 Swap (二分匹配+输出路径)
- 【HDU1507】【最大匹配输出路径match数组】
- hdu 2819 Swap 二分图的最大匹配
- HDU 2819 Swap 最大匹配问题
- HDU 2819 Swap (行列匹配+输出解)
- HDU-2819 swap(二分图最大匹配)
- HDU 2819 ——Swap——————【最大匹配、利用linker数组、邻接表方式】
- HDOJ---1151 Air Raid[匈牙利算法:最小路径覆盖数=原图顶点数–二分图最大匹配数]
- HDU 2819 Swap (二分图-行列匹配+输出解)
- hdoj 4265 Science! 【二分 + 最大流】【求最大完美匹配数并输出完美匹配】
- HDU 2819 Swap 二分图最大匹配
- HDU 2819 Swap (行列匹配+输出解)
- hdu2819 Swap--最大匹配数