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83 lines
1.4 KiB
83 lines
1.4 KiB
12 months ago
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int array[110];
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int n;
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void init(int n) {
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int i = 1;
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while (i <= n * n + 1) {
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array[i] = -1;
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i = i + 1;
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}
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}
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int findfa(int a) {
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if (array[a] == a)
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return a;
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else {
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array[a] = findfa(array[a]);
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return array[a];
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}
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}
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void mmerge(int a, int b) {
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int m = findfa(a);
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int n = findfa(b);
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if (m != n) array[m] = n;
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}
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int main() {
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int t, m;
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int a, b;
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t = 1;
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while (t) {
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t = t - 1;
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n = 4;
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m = 10;
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int i = 0;
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int flag = 0;
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init(n);
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int k = n * n + 1;
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while (i < m) {
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a = getint();
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b = getint();
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if (!flag) {
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int loc = n * (a - 1) + b;
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array[loc] = loc;
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if (a == 1) {
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array[0] = 0;
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mmerge(loc, 0);
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}
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if (a == n) {
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array[k] = k;
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mmerge(loc, k);
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}
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if (b < n && array[loc + 1] != -1) {
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mmerge(loc, loc + 1);
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}
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if (b > 1 && array[loc - 1] != -1) {
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mmerge(loc, loc - 1);
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}
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if (a < n && array[loc + n] != -1) {
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mmerge(loc, loc + n);
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}
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if (a > 1 && array[loc - n] != -1) {
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mmerge(loc, loc - n);
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}
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if (array[0] != -1 && array[k] != -1 && findfa(0) == findfa(k)) {
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flag = 1;
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int tmp = i + 1;
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putint(tmp);
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putch(10);
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}
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}
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i = i + 1;
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}
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if (!flag) {
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putint(-1);
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putch(10);
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}
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}
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return 0;
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}
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