Submission #1029532

#	Time	Username	Problem	Language	Result	Execution time	Memory
1029532		sleepntsheep	Teleporters (IOI08_teleporters)	C11	100 / 100	202 ms	56712 KiB

teleporters

#include <stdio.h>

#define N 1000000
#define A 2000002

int n, m, a[N], b[N], count[A], next[A], o, succ[A], sussy[A], cyclen, cyc[A], ii, END = A - 1, len = -1, cur = 0;

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;

    int last = 0;
    for (int i = 1; i < END; ++i) {
        if (count[i]) {
            if (-1 == succ[0])
                succ[0] = i;
            next[last] = i;
            next[last = i] = END;
            --count[i];
        }
    }

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

    while (cur != END)
        sussy[cur] = 1, ++len, cur = succ[cur];
    sussy[END] = 1;

    for (int i = 0; i < END; ++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 = END - 1; 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:9:5: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
    9 |     scanf("%d%d", &n, &m);
      |     ^~~~~~~~~~~~~~~~~~~~~
teleporters.c:11:9: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   11 |         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
• Subtask 7: 5 / 5
• Subtask 8: 5 / 5
• Subtask 9: 5 / 5
• Subtask 10: 5 / 5
• Subtask 11: 5 / 5
• Subtask 12: 5 / 5
• Subtask 13: 5 / 5
• Subtask 14: 5 / 5
• Subtask 15: 5 / 5
• Subtask 16: 5 / 5
• Subtask 17: 5 / 5
• Subtask 18: 5 / 5
• Subtask 19: 5 / 5
• Subtask 20: 5 / 5