41 lines
1.0 KiB
C++
41 lines
1.0 KiB
C++
#include <iostream>
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#include <algorithm>
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using namespace std;
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const int maxn = 1000000 + 10;
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struct Node{
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int a, b, val;
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}node[maxn];
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int parent[maxn];
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bool cmp(const Node &a, const Node &b){
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return a.val < b.val ;
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}
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void Init(int num){
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for(int i=0; i<num; i++)
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parent[i] = i;
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}
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int main(){
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int n, m;
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while(cin >>n >>m, n||m){
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int ans = 0, i;
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for( i=0; i<m; i++){
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cin >>node[i].a >>node[i].b >>node[i].val;
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}
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sort(node, node+m, cmp);
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Init(n);
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for( i=0; i<m; i++){
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if( node[i].a == parent[node[i].a] || node[i].b == parent[node[i].b])
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ans = ans > node[i].val ? ans : node[i].val;
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parent[ node[i].a ] = -1;
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parent[ node[i].b ] = -1;
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}
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for( i=0; i<n; i++)
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if(parent[i] == i)
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break;
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if(i < n)
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cout <<"IMPOSSIBLE" <<endl;
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else
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cout <<ans <<endl;
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}
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return 0;
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}
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