ZOJ 2027 最短路

保存一下路上最大值，在更新的条件中也改成路径和减去最大值即可

SPFA

#include <set>
#include <cmath>
#include <queue>
#include <stack>
#include <string>
#include <cstdio>
#include <cstring>
#include <iostream>
#include <map>
#include <algorithm>
using namespace std;

typedef  long long LL;
const double PI = acos(-1.0);

template <class T> inline  T MAX(T a, T b){if (a > b) return a;return b;}
template <class T> inline  T MIN(T a, T b){if (a < b) return a;return b;}

const int N = 111;
const int M = 11111;
const LL MOD = 1000000007LL;
const int dir[4][2] = {1, 0, -1, 0, 0, -1, 0, 1};
const int INF = 0x3f3f3f3f;


struct node
{
	int v, next, w;
}edge[222];

int head[222],idx;
int mx[222], dist[222], inq[222];
int cnt;

inline void addnode(int u, int v, int w)
{
	edge[idx].v = v; edge[idx].w = w;
	edge[idx].next = head[u]; head[u] = idx++;
}

void spfa()
{
	int i, j, k, u, v, w;
	queue < int > q;
	fill(dist, dist + cnt + 1, INF);
	memset(mx, 0, sizeof(mx));
	memset(inq, 0, sizeof(inq));
	dist[1] = 0; inq[1] = 1; q.push(1);
	while (!q.empty())
	{
		u = q.front(); q.pop(); inq[u]--;
		for (i = head[u]; ~i; i = edge[i].next)
		{
			v = edge[i].v; w = edge[i].w;
			if (dist[u] + w - MAX(mx[u], w) < dist[v] - mx[v])
			{
				dist[v] = dist[u] + w;
				mx[v] = MAX(mx[u], w);
				if (!inq[v]) {inq[v]++; q.push(v);}
			}
		}
	}
}



int main()
{
	string name1, name2;
	while (cin >> name1 >> name2)
	{
		int i, j, k,  n, m, u, v, w;
		map <string, int> index;cnt = 1;
		memset(head, -1, sizeof(head));
		idx = 0;
		index[name1] = cnt++;
		index[name2] = cnt++;
		cin >> m;
		for (i = 0; i < m; ++i)
		{
			cin >> name1 >> name2 >> w;
			if (!index[name1]) u = index[name1] = cnt++;
			else u = index[name1];
			if (!index[name2]) v = index[name2] = cnt++;
			else v = index[name2];
			addnode(u, v, w);
		}
		spfa();
		printf("%d\n", dist[2] - mx[2]);
	}
	return 0;
}