poj 3680 Intervals

#include<iostream>
using namespace std;
const int nMax = 405;
const int eMax = 1500;

struct{
int st, ed, w;
}inl[nMax];
struct{
int v, cap, cost, next, re;
}edge[eMax];
int n, ans;
int k, edgeHead[nMax];
int que[nMax], pre[nMax], dis[nMax];
bool vis[nMax];
int hash[100005];

void addEdge(int u, int v, int ca, int co){
edge[k].v = v;
edge[k].cap = ca;
edge[k].cost = co;
edge[k].next = edgeHead[u];
edge[k].re = k + 1;
edgeHead[u] = k ++;
edge[k].v = u;
edge[k].cap = 0;
edge[k].cost = -co;
edge[k].next = edgeHead[v];
edge[k].re = k - 1;
edgeHead[v] = k ++;
}

bool spfa(){
int i, head = 0, tail = 1;
for(i = 0; i <= n; i ++){
dis[i] = -1;
vis[i] = false;
}
dis[0] = 0;
que[0] = 0;
vis[0] = true;
while(head != tail){
int u = que[head];
for(i = edgeHead[u]; i != -1; i = edge[i].next){
int v = edge[i].v;
if(edge[i].cap && dis[v] < dis[u] + edge[i].cost){
dis[v] = dis[u] + edge[i].cost;
pre[v] = i;
if(!vis[v]){
vis[v] = true;
que[tail ++] = v;
if(tail == nMax) tail = 0;
}
}
}
vis[u] = false;
head ++;
if(head == nMax) head = 0;
}
if(dis
<= 0) return false;
return true;
}

void end(){
int u, p;
for(u = n; u != 0; u = edge[edge[p].re].v){
p = pre[u];
edge[p].cap -= 1;
edge[edge[p].re].cap += 1;
ans += edge[p].cost;
}
}

int main(){
int t, i, N, K;
scanf("%d", &t);
while(t --){
memset(edgeHead, -1, sizeof(edgeHead));
memset(hash, 0, sizeof(hash));
scanf("%d%d", &N, &K);
for(i = 0; i < N; i ++){
scanf("%d%d%d", &inl[i].st, &inl[i].ed, &inl[i].w);
hash[inl[i].st] = hash[inl[i].ed] = 1;
}
for(k = 1, i = 0; i <= 100000; i ++)     //  由于100000不大，所以我用hash离散化。
if(hash[i] == 1)
hash[i] = k ++;
for(i = 0; i < N; i ++){                 //  线段的端点值，改为离散后的下标号。
inl[i].st = hash[inl[i].st];
inl[i].ed = hash[inl[i].ed];
}
n = k; k = 0;
for(i = 0; i < n; i ++)                  //  建图。
addEdge(i, i+1, K, 0);
for(i = 0; i < N; i ++)
addEdge(inl[i].st, inl[i].ed, 1, inl[i].w);
ans = 0;
while(spfa()) end();
printf("%d\n", ans);
}
return 0;
}