34 lines
834 B
C++
34 lines
834 B
C++
#include <cstdio>
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#include <algorithm>
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#include <cstring>
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using namespace std;
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typedef long long ll;
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int main(void) {
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ll n, m, x, y;
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while (scanf ("%I64d%I64d%I64d%I64d", &n, &m, &x, &y) == 4) {
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if (n > m) {
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swap (n, m); swap (x, y);
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}
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if (x > n - x + 1) {
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x = n - x + 1;
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}
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if (y > m - y + 1) {
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y = m - y + 1;
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}
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ll hm = (m + 1) / 2, hn = (n + 1) / 2;
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ll ans = min (hm, hn);
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if (m == n) {
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if (m % 2 == 1) {
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if (x == hn && y == hm) ans--;
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}
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}
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else {
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ll t = min (y, n - x);
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ans = max (ans, t);
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ans = min (ans, hm);
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}
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printf ("%I64d\n", ans);
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}
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return 0;
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}
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