1111. Online Map (30)

这题是真TM复杂。。。感觉考试的时候绝对做不出来。。。dijsktra的算法还是要再熟悉熟悉。。。基础真的还是太差。。。

 

其实就是两次dij，然后要记住路径，我用了pre[501]来存储前一个节点，最后再倒着走回来，不知道这么写是不是有点复杂了。。。 

#include<iostream>
#include<string>
#include<map>
#include<vector>
#include<algorithm>
#include<queue>
#include<set>
#include<stack>
using namespace std;
const int INF = 99999999;
int tim[501][501];
int length[501][501];
int n, m;
int s, d;

int t[501];
int l[501];
int inter[501];
int pre[501];
int vist[501];

void dij() {
    for (int i = 0; i < n; i++) {
        int u = -1; int MIN = INF;
        for (int j = 0; j < n; j++) {
            if (vist[j] == 0 && MIN > t[j]) {
                u = j;
                
                MIN = t[j];
            }
        }
        if (u == -1) break;
        vist[u] = 1;

        for (int v = 0; v < n; v++) {
            if (vist[v] == 0 && tim[u][v] != INF) {
                if (t[u] + tim[u][v] < t[v]) {
                    
                    t[v] = t[u] + tim[u][v];
                    inter[v] = inter[u] + 1;
                    pre[v] = u;
                }

                else if (t[u] + tim[u][v] == t[v] && inter[v] > inter[u] + 1) {
                    t[v] = t[u] + tim[u][v];
                    inter[v] = inter[u] + 1;
                    pre[v] = u;
                }
            }
        }
    }
}

void dij2() {
    for (int i = 0; i < n; i++) {
        int u = -1; int MIN = INF;
        for (int j = 0; j < n; j++) {
            if (vist[j] == 0 && MIN > l[j]) {
                u = j;

                MIN = l[j];
            }
        }
        if (u == -1) break;
        vist[u] = 1;

        for (int v = 0; v < n; v++) {
            if (vist[v] == 0 && length[u][v] != INF) {
                if (l[u] + length[u][v] < l[v]) {
                    l[v] = l[u] + length[u][v];
                    t[v] = t[u] + tim[u][v];
                    
                    pre[v] = u;
                }

                else if (t[u] + tim[u][v] < t[v] && l[u] + length[u][v] == l[v]) {
                    l[v] = l[u] + length[u][v];
                    t[v] = t[u] + tim[u][v];

                    pre[v] = u;
                }
            }
        }
    }
}


int main() {
    cin >> n >> m;
    fill(tim[0], tim[0] + (501 * 501), INF);
    fill(length[0], length[0] + (501 * 501), INF);
    for (int i = 0; i < m; i++) {
        int t1, t2, ow, t, l;
        cin >> t1 >> t2 >> ow >> l >> t;

        if (ow == 0) {
            tim[t1][t2] = tim[t2][t1] = t;
            length[t1][t2] = length[t2][t1] = l;
        }

        else {
            tim[t1][t2] = t;
            length[t1][t2] = l;
        }
    }


    cin >> s >> d;

    
    fill(t, t + 501, INF);
    t[s] = 0;
    fill(vist, vist + 501, 0);

    dij();



    int z = d;
    int totalt = 0;
    vector<int> p1;
    vector<int> p2;
    while (z != s) {
        p1.push_back(z);
        totalt += tim[pre[z]][z];
        z = pre[z];
    }
    reverse(p1.begin(), p1.end());


    fill(vist, vist + 501, 0);
    fill(pre, pre + 501, 0);
    fill(t, t + 501, INF);
    fill(l, l + 501, INF);
    l[s] = 0;

    dij2();

    
    int totald = 0;
    z = d;
    while (z != s) {
        p2.push_back(z);
        totald += length[pre[z]][z];
        z = pre[z];
    }
    reverse(p2.begin(), p2.end());

    if (p1 != p2) {
    printf("Distance = %d: ", totald);
    printf("%d", s);


    for (int i = 0; i < p2.size(); i++) {
        printf(" -> %d", p2[i]);
    }
    cout << endl;

    printf("Time = %d: ", totalt);
    printf("%d", s);
    

    for (int i = 0; i < p1.size(); i++) {
        printf(" -> %d", p1[i]);
    }

    }


    else {
        printf("Distance = %d; ", totald);
        printf("Time = %d: ", totalt);
        printf("%d", s);


        for (int i = 0; i < p1.size(); i++) {
            printf(" -> %d", p1[i]);
        }

    }
    
    
    system("pause");
    
}