Submission #56492

#	Time	Username	Problem	Language	Result	Execution time	Memory
56492		aquablitz11	Teleporters (IOI08_teleporters)	C++14	100 / 100	752 ms	43060 KiB

teleporters

#include <stdio.h>
#include <stdlib.h>

#define N 1000001

int n, m;
int A[N], B[N], pos[2*N], coord[2*N], cc;

int comp(const void *a, const void *b) {
    return *(int*)a - *(int*)b;
}

int main()
{
    scanf("%d%d", &n, &m);
    for (int i = 0; i < n; ++i) {
        scanf("%d%d", &A[i], &B[i]);
        coord[2*i+1] = A[i];
        coord[2*i+2] = B[i];
    }
    qsort(coord, 2*n+1, sizeof(int), comp);
    for (int i = 0; i < 2*n+1; ++i)
        pos[coord[i]] = i;
    for (int i = 0; i < n; ++i) {
        A[i] = pos[A[i]];
        B[i] = pos[B[i]];
    }
    for (int i = 0; i < n; ++i) {
        pos[A[i]-1] = B[i];
        pos[B[i]-1] = A[i];
    }
    for (int i = 0; i < 2*n+1; ++i)
        coord[i] = 0;

    int ans = 0;
    for (int s = 0; s < 2*n; ++s) {
        if (coord[s]) continue;
        for (int u = s, c = 1; ; ++c) {
            coord[u] = 1;
            u = pos[u];
            if (coord[u]) {
                A[cc++] = c;
                break;
            } else if (u == 2*n) {
                ans = c;
                break;
            }
        }
    }
    qsort(A, cc, sizeof(int), comp);
    while (m--) {
        if (cc > 0) {
            ans += A[--cc]+2;
        } else {
            ++ans;
            A[cc++] = 1;
        }
    }
    printf("%d\n", ans);

    return 0;
}

Compilation message (stderr)

teleporters.cpp: In function 'int main()':
teleporters.cpp:15:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%d", &n, &m);
     ~~~~~^~~~~~~~~~~~~~~~
teleporters.cpp:17:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d%d", &A[i], &B[i]);
         ~~~~~^~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 5 / 5
• Subtask 2: 5 / 5
• Subtask 3: 5 / 5
• Subtask 4: 5 / 5
• Subtask 5: 5 / 5
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• Subtask 20: 5 / 5