2024-06-02 22:04:54 +08:00
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#include "sylib.h"
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2024-06-14 13:25:10 +08:00
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int quick_read(){
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int ch = getch(); int x = 0, f = 0;
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while (ch < 48 || ch > 57){
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if (ch == 45) f = 1;
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ch = getch();
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}
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while (ch >= 48 && ch <=57){
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x = x * 10 + ch - 48;
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ch = getch();
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}
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if (f) return -x;
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else return x;
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}
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#define maxm 1005
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#define maxn 105
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int n, m;
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int u[maxm], v[maxm], c[maxm], fa[maxm];
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int find(int x){
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if (x == fa[x]) return x;
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int asdf = find(fa[x]);
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fa[x] = asdf;
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return asdf;
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}
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int same(int x, int y){
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x = find(x);
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y = find(y);
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if (x == y) return 1;
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return 0;
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}
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int prim(){
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int i = 0;
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while (i < m){
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int j = i + 1;
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while (j < m){
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if (c[i] > c[j]){
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int t = u[i];
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u[i] = u[j];
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u[j] = t;
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t = v[i];
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v[i] = v[j];
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v[j] = t;
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t = c[i];
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c[i] = c[j];
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c[j] = t;
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}
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j = j + 1;
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}
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i = i + 1;
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}
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i = 1;
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while (i <= n){
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fa[i] = i;
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i = i + 1;
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}
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i = 0;
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int res = 0;
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while (i < m){
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if (same(u[i], v[i])) continue;
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res = res + c[i];
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fa[find(u[i])]=v[i];
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i = i + 1;
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}
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return res;
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}
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int main(){
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int n = quick_read(), m = quick_read();
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int i = 0;
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while (i < m){
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u[i] = quick_read();
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v[i] = quick_read();
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c[i] = quick_read();
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i = i + 1;
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}
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return prim();
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}
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