1087. All Roads Lead to Rome (30)解题报告

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代码

#include <iostream>#include <cstdio>#include <cstdlib>#include <stack>#include <queue>#include <vector>#include <string>#include <functional>#include <map>#define N 220#define INF 1000000using namespace std;bool dijkstra(void);int dfs(int c, int num, int tmp_h, int tmp_cost);int n, k, max_happiness = 0, min_cost = INF, tmp_h = 0;double averg_happy = 0.0;string start;int matrix[N][N], happiness[N] = { 0 };vector<int> v[N];stack<int> path, tmp_path;map<string, int> mp;map<int, string> remp;int main(int argc, const char * argv[]) {    cin >> n >> k >> start;    string city1, city2;    int happy, cost;    int i, j;    for (i = 0; i < n; i++) {        for (j = 0; j < n; j++) {            matrix[i][j] = INF;        }    }    mp[start] = 0;    remp[0] = start;    for(i = 1; i < n; i++){        cin >> city1 >> happy;        mp[city1] = i;        happiness[i] = happy;        remp[i] = city1;    }    for(i = 0; i < k; i++){        cin >> city1 >> city2 >> cost;        matrix[mp[city1]][mp[city2]] = cost;        matrix[mp[city2]][mp[city1]] = cost;    }    dijkstra();    int dest = mp[string("ROM")];    int cnt;    cnt = dfs(dest, 1, 0, 0);    printf("%d %d %d %d\n", cnt, min_cost, max_happiness, (int)averg_happy);    int tmp = path.top();    path.pop();    cout << remp[tmp];    while(!path.empty()){        tmp = path.top();        path.pop();        cout << "->" << remp[tmp];    }    cout << endl;    return 0;}bool dijkstra(void){    int i, j, k, min_cost, index = 0, dis[N];    bool isvisited[N];    size_t h1, h2;    string c1, c2;    for (i = 0; i < n; i++) {        dis[i] = INF;        isvisited[i] = false;    }    dis[mp[start]] = 0;    for(i = 0; i < n; i++){        min_cost = INF;        for(j = 0; j < n; j++){            if (!isvisited[j] && min_cost > dis[j]) {                min_cost = dis[j];                index = j;            }        }        isvisited[index] = true;        for(j = 0; j < n; j++){            if (!isvisited[j] && dis[index] + matrix[index][j] < dis[j]) {                dis[j] = dis[index] + matrix[index][j];                v[j].clear();                v[j].push_back(index);            }            else if (!isvisited[j] && dis[index] + matrix[index][j] == dis[j]) {                v[j].push_back(index);            }        }    }    return true;}int dfs(int c, int num, int tmp_h, int tmp_cost){    static int cnt = 0;    int i;    if (c == 0) {        cnt++;        tmp_path.push(c);        if (tmp_cost < min_cost || (tmp_cost == min_cost && tmp_h > max_happiness) || (tmp_cost == min_cost && tmp_h == max_happiness && (double)tmp_h / (num - 1) > averg_happy)) {            path = tmp_path;            min_cost = tmp_cost;            max_happiness = tmp_h;            averg_happy = tmp_h / (num - 1);        }        tmp_path.pop();        return cnt;    }    else {        tmp_h += happiness[c];        tmp_path.push(c);        for (i = 0; i < v[c].size(); i++) {            tmp_cost += matrix[c][v[c][i]];            dfs(v[c][i], num + 1, tmp_h, tmp_cost);            tmp_cost -= matrix[c][v[c][i]];        }        tmp_path.pop();        return cnt;    }}
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