やるだけって言って解いてほしい感じの問題。

## implementation

#include <algorithm>
#include <cstdio>
#include <queue>
#include <tuple>
#include <vector>
#define repeat(i, n) for (int i = 0; (i) < int(n); ++(i))
#define repeat_from(i, m, n) for (int i = (m); (i) < int(n); ++(i))
#define whole(f, x, ...) ([&](decltype((x)) whole) { return (f)(begin(whole), end(whole), ## __VA_ARGS__); })(x)
using namespace std;
constexpr int inf = 1e9+7;
constexpr int root = 0;
int main() {
while (true) {
// input
int n, m; scanf("%d%d", &n, &m);
if (n == 0 and m == 0) break;
vector<vector<tuple<int, int, int> > > g(n);
repeat (i, m) {
int u, v, d, c; scanf("%d%d%d%d", &u, &v, &d, &c); -- u; -- v;
g[u].emplace_back(v, d, c);
g[v].emplace_back(u, d, c);
}
// solve
// // dijkstra
vector<int> dist(n, inf); {
priority_queue<pair<int, int> > que;
dist[root] = 0;
que.emplace(- dist[root], root);
while (not que.empty()) {
int cost, i; tie(cost, i) = que.top(); que.pop();
if (dist[i] < - cost) continue;
for (auto edge : g[i]) {
int j, d; tie(j, d, ignore) = edge;
if (- cost + d < dist[j]) {
dist[j] = - cost + d;
que.emplace(cost - d, j);
}
}
}
}
// // make the tree
vector<vector<int> > h(n);
repeat (i, n) {
for (auto edge : g[i]) {
int j, d, c; tie(j, d, c) = edge;
if (dist[i] + d == dist[j]) {
h[j].push_back(c);
}
}
}
int result = 0;
repeat_from (i, 1, n) {
result += *whole(min_element, h[i]);
}
// output
printf("%d\n", result);
}
return 0;
}