题目连接：https://codeforces.com/contest/1517/problem/B
The 2050 volunteers are organizing the “Run! Chase the Rising Sun” activity. Starting on Apr 25 at 7:30 am, runners will complete the 6km trail around the Yunqi town.
There are n+1 checkpoints on the trail. They are numbered by 0, 1, …, n. A runner must start at checkpoint 0 and finish at checkpoint n. No checkpoint is skippable — he must run from checkpoint 0 to checkpoint 1, then from checkpoint 1 to checkpoint 2 and so on. Look at the picture in notes section for clarification.
Between any two adjacent checkpoints, there are m different paths to choose. For any 1≤i≤n, to run from checkpoint i?1 to checkpoint i, a runner can choose exactly one from the m possible paths. The length of the j-th path between checkpoint i?1 and i is bi,j for any 1≤j≤m and 1≤i≤n.
To test the trail, we have m runners. Each runner must run from the checkpoint 0 to the checkpoint n once, visiting all the checkpoints. Every path between every pair of adjacent checkpoints needs to be ran by exactly one runner. If a runner chooses the path of length li between checkpoint i?1 and i (1≤i≤n), his tiredness is
mini=1nli,
i. e. the minimum length of the paths he takes.
Please arrange the paths of the m runners to minimize the sum of tiredness of them.
Input
Each test contains multiple test cases. The first line contains the number of test cases t (1≤t≤10000). Description of the test cases follows.
The first line of each test case contains two integers n and m (1≤n,m≤100).
The i-th of the next n lines contains m integers bi,1, bi,2, …, bi,m (1≤bi,j≤109).
It is guaranteed that the sum of n?m over all test cases does not exceed 104.
Output
For each test case, output n lines. The j-th number in the i-th line should contain the length of the path that runner j chooses to run from checkpoint i?1 to checkpoint i. There should be exactly m integers in the i-th line and these integers should form a permuatation of bi,1, …, bi,m for all 1≤i≤n.
If there are multiple answers, print any.
Example
input
2
2 3
2 3 4
1 3 5
3 2
2 3
4 1
3 5
output
2 3 4
5 3 1
2 3
4 1
3 5
分析
只需要把所有数中前 m 小的数分别放在不同的列中即可。
可以用 multiset 来维护
代码
#include<bits/stdc++.h>
using namespace std;
typedef long long ll;int n,m;
int a[200][200],vis[100];struct node{
int s,x,y;bool operator < (const node & b) const{
return s < b.s;}
};multiset<node> q;
multiset<node>::iterator it,tt;void change(int s,int t,int x,int y,int a,int b)
{
node tmp;tmp.s = s;tmp.x = a;tmp.y = b;it = q.lower_bound(tmp);while((*it).x != x || (*it).y != y) it++;q.erase(it);q.insert(tmp);
}int main() {
int T = 1;scanf("%d",&T);while(T--){
memset(vis, 0, sizeof(vis));q.clear();scanf("%d%d",&n,&m);for(int i=1;i<=n;i++){
for(int j=1;j<=m;j++){
scanf("%d",&a[i][j]);node t;t.s = a[i][j];t.x = i;t.y = j;q.insert(t);}}int tmp = m;int begin = 1;while(tmp){
it = q.begin();node now = *it;q.erase(it);if(vis[now.y] == 0){
vis[now.y] = 1;tmp--;continue;}for(int i=begin;i<=m;i++){
if(vis[i] == 1) continue;vis[i] = 1;change(a[now.x][i],a[now.x][now.y],now.x,i,now.x,now.y);swap(a[now.x][i],a[now.x][now.y]);tmp--;begin = i + 1;break;}}for(int i=1;i<=n;i++){
for(int j=1;j<=m;j++){
printf("%d ",a[i][j]);}printf("\n");}}return 0;
}