矩阵快速幂加速板题

#include<bits/stdc++.h>
#define int long long
using namespace std;
int arr[101000], tot = 0;
struct node{
	int matrix[110][110];
	node operator *(node b) const {
		node ans; memset(ans.matrix, 0x3f, sizeof ans.matrix);
		for(int k=1; k<=tot; ++k) {
			for(int i=1; i<=tot; ++i) {
				for(int j=1; j<=tot; ++j) {
					ans.matrix[i][j] = min(matrix[i][k] + b.matrix[k][j],ans.matrix[i][j]);
				}
			}
		}
		return ans;
	}
};
struct node2{
	int from, to, w;
}edge[101000];
int getid(int index) {
	return lower_bound(arr+1, arr+1+tot, index)-arr;
}
node Pow(node m, int u) {
	if(u==1) {
		return m;
	}
	node temp = Pow(m, u/2);
	if(u&1) {
		return temp*temp*m;
	} else {
		return temp*temp;
	}
} 
signed main() {
	int n, t, s, e; cin >> n >> t >> s >> e;//s->e n edges
	int maxn = 0;
	for(int i=1; i<=t; ++i) {
		cin >> edge[i].from >> edge[i].to >> edge[i].w;
		arr[++tot] = edge[i].from;
		arr[++tot] = edge[i].to;
	}
	sort(arr+1,arr+1+tot);
	tot = unique(arr+1, arr+1+tot)-arr-1;
	node now;memset(now.matrix, 0x3f, sizeof now.matrix);
	for(int i=1; i<=t; ++i) {
		now.matrix[getid(edge[i].from)][getid(edge[i].to)] = edge[i].w;
		now.matrix[getid(edge[i].to)][getid(edge[i].from)] = edge[i].w;
	}
	if(n==1) {
		cout << now.matrix[getid(s)][getid(e)];
		return 0;
	}
	node as = Pow(now, n-1);
	cout << as.matrix[getid(s)][getid(e)];
	return 0;
}