Submission #356368

#	Time	Username	Problem	Language	Result	Execution time	Memory
356368		sean617	Dreaming (IOI13_dreaming)	C++98	47 / 100	170 ms	25324 KiB

dreaming

#include "dreaming.h"
#include <iostream>
#include <cstdio>
#include <vector>
#define SZ 100005
using namespace std;

int MM = 2e9;
int n, m, mx, po, cnt, mn, md, ans, m1, m2, m3, v[SZ], h1[SZ], h2[SZ], num1[SZ], num2[SZ];
vector<int> a[SZ], b[SZ], c;
//void f(int p, int q, int w) {
//    int i, t;
//    if (w > mx) {
//        mx = w;
//        po = p;
//    }
//    v[p] = cnt;
//    for (i = 0; i < a[p].size(); i++) {
//        t = a[p][i];
//        if (t == q) continue;
//        f(t, p, w + b[p][i]);
//    }
//}
//
//int g(int p, int q, int w) {
//    int i, t, t2;
//    if (w == mx) return 1;
//    for (i = 0; i < a[p].size(); i++) {
//        t = a[p][i];
//        if (t == q) continue;
//        if (g(t, p, w + b[p][i])) {
//            t2 = max(w, mx - w);
//            mn = min(mn, t2);
//            return 1;
//        }
//    }
//    return 0;
//}

int f(int p, int q) {
    int i, t, mx1 = 0, mx2 = 0, t2, n1, n2;
    v[p] = cnt;
    for (i =0 ; i < a[p].size(); i++) {
        t = a[p][i];
        if (t == q) continue;
        t2 = f(t, p) + b[p][i];
        if (t2 > mx1) {
            n2 = n1;
            n1 = t;
            mx2 = mx1;
            mx1 = t2;
        } else if (t2 > mx2) {
            mx2 = t2;
            n2 = t;
        }
    }
    h1[p] = mx1;
    h2[p] = mx2;
    num1[p] = n1;
    num2[p] = n2;
    return mx1;
}

int g(int p, int q, int w) {
    int i, t, tt, t1, mx1 = 0;
    for (i = 0; i < a[p].size(); i++) {
        t = a[p][i];
        if (t == q) continue;
        if (num1[p] == t) t1 = h2[p];
        else t1 = h1[p];
        t1 = max(t1, w);
        mx1 = max(mx1, g(t, p, t1 + b[p][i]) + b[p][i]);
    }
    tt = max(w, mx1);
    mx = max(mx, tt);
    mn = min(mn, tt);
    return mx1;
}

int travelTime(int N, int M, int L, int A[], int B[], int T[]) {
    int i, j, t1, t2, t3;
    n = N;
    m = M;
    for (i = 0; i < m; i++) {
//        scanf ("%d %d %d", &t1, &t2, &t3);
        t1 = A[i];
        t2 = B[i];
        t3 = T[i];
        a[t1].push_back(t2);
        a[t2].push_back(t1);
        b[t1].push_back(t3);
        b[t2].push_back(t3);
    }
    for (i = 0; i < n; i++) {
        if (v[i]) continue;
        cnt++;
        mx = 0;
        mn = MM;
        f(i, 0);
        g(i, 0, 0);
//        mx = -1;
//        c.clear();
//        f(i, 0, 0);
//        c.push_back(po);
//        mx = -1;
//        f(po, 0, 0);
//        ans = max(ans, mx);
//        c.push_back(po);
//        if (mx == 0) {
//            continue;
//        }
//        mn = MM;
//        g(c[0], 0, 0);
        if (mn > m1) {
            m3 = m2;
            m2 = m1;
            m1 = mn;
        } else if (mn > m2) {
            m3 = m2;
            m2 = mn;
        } else if (mn > m3) {
            m3 = mn;
        }
        ans = max(ans, mx);
//        printf("%d %d\n", c[0], c[1]);
    }
    if (m == n - 1) {
        cout << ans;
        return 0;
    }
    ans = max(ans, m1 + m2 + L);
    if (cnt >= 3) ans = max(ans, m2 + m3 + L * 2);
    return ans;
}

Compilation message (stderr)

dreaming.cpp: In function 'int f(int, int)':
dreaming.cpp:43:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   43 |     for (i =0 ; i < a[p].size(); i++) {
      |                 ~~^~~~~~~~~~~~~
dreaming.cpp: In function 'int g(int, int, int)':
dreaming.cpp:66:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   66 |     for (i = 0; i < a[p].size(); i++) {
      |                 ~~^~~~~~~~~~~~~
dreaming.cpp: In function 'int travelTime(int, int, int, int*, int*, int*)':
dreaming.cpp:81:12: warning: unused variable 'j' [-Wunused-variable]
   81 |     int i, j, t1, t2, t3;
      |            ^
dreaming.cpp: In function 'int f(int, int)':
dreaming.cpp:60:13: warning: 'n2' may be used uninitialized in this function [-Wmaybe-uninitialized]
   60 |     num2[p] = n2;
      |     ~~~~~~~~^~~~
dreaming.cpp:59:13: warning: 'n1' may be used uninitialized in this function [-Wmaybe-uninitialized]
   59 |     num1[p] = n1;
      |     ~~~~~~~~^~~~

• Subtask 1: 14 / 14
• Subtask 2: 10 / 10
• Subtask 3: 23 / 23
• Subtask 4: 0 / 18
• Subtask 5: 0 / 12
• Subtask 6: 0 / 23