mirror of
https://github.com/Kiritow/OJ-Problems-Source.git
synced 2024-03-22 13:11:29 +08:00
87 lines
2.1 KiB
C++
87 lines
2.1 KiB
C++
#include <iostream>
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#include <cstdlib>
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#include <cstdio>
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#include <cstring>
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#include <queue>
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using namespace std;
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const int SIZE = 10010;
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const int INF = 0xfffffff;
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int u[5*SIZE], v[5*SIZE], w[5*SIZE], nex[5*SIZE], h[5*SIZE];
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int first[SIZE], d[SIZE];
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int n, m, cnt;
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int s, e;
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void read_graph(int u1, int v1, int w1, int h1)
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{
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u[cnt] = u1; v[cnt] = v1; w[cnt] = w1; h[cnt] = h1;
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nex[cnt] = first[u[cnt]];
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first[u[cnt]] = cnt++;
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}
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int spfa(int src, int mid)
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{
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queue<int> q;
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bool inq[SIZE] = {0};
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for(int i = 1; i <= n; i++) d[i] = (i == src)?0:INF;
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q.push(src);
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while(!q.empty())
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{
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int x = q.front(); q.pop();
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inq[x] = 0;
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for(int e = first[x]; e!=-1; e = nex[e]) if(d[v[e]] > d[x]+w[e] && mid <= h[e])
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{
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d[v[e]] = d[x] + w[e];
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if(!inq[v[e]])
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{
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inq[v[e]] = 1;
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q.push(v[e]);
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}
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}
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}
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if(d[e] == INF) return 0;
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return 1;
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}
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void init()
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{
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memset(first, -1, sizeof(first));
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cnt = 0;
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}
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int main()
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{
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int times = 0;
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while(~scanf("%d%d", &n, &m), n, m)
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{
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init();
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while(m--)
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{
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int u1, v1, w1, h1;
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scanf("%d%d%d%d", &u1, &v1, &h1, &w1);
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if(h1 == -1) h1 = INF;
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read_graph(u1, v1, w1, h1);
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read_graph(v1, u1, w1, h1);
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}
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int x = 0, y, ans = INF, mid, h;
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scanf("%d%d%d", &s, &e, &y);
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while(x <= y)
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{
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mid = (x+y)>>1;
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if(spfa(s, mid))
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{
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x = mid+1;
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ans = d[e];
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h = mid;
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}
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else y = mid-1;
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}
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if(times) printf("\n");
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printf("Case %d:\n", ++times);
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if(ans != INF)
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{
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printf("maximum height = %d\n", h);
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printf("length of shortest route = %d\n", ans);
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}
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else
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{
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printf("cannot reach destination\n");
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}
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}
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}
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