Submission #1029528

#	Time	Username	Problem	Language	Result	Execution time	Memory
1029528		sleepntsheep	Teleporters (IOI08_teleporters)	C11	100 / 100	232 ms	65536 KiB

teleporters

#include <stdio.h>

#define N 1000000
#define A 2000002

int pos[2*N], n, m, a[N], b[N], count[A], next[A], o;
int succ[A], sussy[A], cyclen, cyc[A], ii;

int main() {
    scanf("%d%d", &n, &m);
    for (int i = 0; i < n; ++i)
        scanf("%d%d", a+i, b+i),
        ++count[a[i]], ++count[b[i]];
    for (int i = 0; i < sizeof succ / sizeof *succ; ++i)
        succ[i] = -1;

    for (int o = 0, i = 0; i < A; ++i)
        while (count[i]) pos[o++] = i, --count[i];

    for (int i = 1; i < 2 * n; ++i)
        next[pos[i-1]] = pos[i];
    next[pos[2*n-1]] = 2000001;

    succ[0] = pos[0];

    for (int i = 0; i < n; ++i)
        succ[a[i]] = next[b[i]], succ[b[i]] = next[a[i]];

    int len = -1, cur = 0;
    while (cur != 2000001)
        sussy[cur] = 1, ++len, cur = succ[cur];
    sussy[2000001] = 1;

    for (int i = 0; i <= 2000000; ++i) {
        if (-1 < succ[i] && !sussy[i]) {
            cyclen = 1;
            cur = succ[i];
            sussy[i] = -1;
            while (cur != i)
                ++cyclen, sussy[cur] = -1, cur = succ[cur];
            ++count[cyclen];
        }
    }

    for (int i = 2000000; i >= 1; --i)
        while (count[i]) cyc[o++] = i, --count[i];

    while (ii < o && m)
        --m, len += cyc[ii++] + 2;

    len += 4 * (m / 2);
    if (m & 1) ++len;
    printf("%d", len);


    return 0;
}

Compilation message (stderr)

teleporters.c: In function 'main':
teleporters.c:10:5: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   10 |     scanf("%d%d", &n, &m);
      |     ^~~~~~~~~~~~~~~~~~~~~
teleporters.c:12:9: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   12 |         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
• Subtask 6: 5 / 5
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• Subtask 8: 5 / 5
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• Subtask 12: 5 / 5
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• Subtask 15: 5 / 5
• Subtask 16: 5 / 5
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• Subtask 19: 5 / 5
• Subtask 20: 5 / 5