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https://git.sb/baoshuo/OI-codes.git
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45 lines
941 B
C++
45 lines
941 B
C++
#include <bits/stdc++.h>
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using namespace std;
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int n, k, p, trie[10000005][2], size[10000005];
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char s[100005];
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bool a[100005];
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void calcsize(int u) {
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if (trie[u][0]) calcsize(trie[u][0]);
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if (trie[u][1]) calcsize(trie[u][1]);
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size[u] += size[trie[u][0]] + size[trie[u][1]];
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}
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void print(int u, int k) {
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if (u != 1 && k-- == 1) {
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cout << endl;
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exit(0);
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}
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if (size[trie[u][0]] >= k) {
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cout << 0;
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print(trie[u][0], k);
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} else {
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cout << 1;
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print(trie[u][1], k - size[trie[u][0]]);
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}
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}
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int main() {
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cin >> n >> k >> s + 1;
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for (int i = 1; i <= n; i++) {
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a[i] = s[i] - '0';
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}
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p = 1;
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for (int i = 1; i <= n; i++) {
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int u = 1;
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for (int j = i; j <= min(n, i + k - 1); j++) {
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size[u = (trie[u][a[j]] ? trie[u][a[j]] : trie[u][a[j]] = ++p)] = 1;
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}
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}
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calcsize(1);
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print(1, k);
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return 0;
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}
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