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49 lines
924 B
C++
49 lines
924 B
C++
#include <iostream>
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#include <string>
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using std::cin;
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using std::cout;
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const char endl = '\n';
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const int N = 1e6 + 5;
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int t, n;
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int cnt, len[N];
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int cnt_odd, cnt_even;
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std::string s;
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long long ans;
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int main() {
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std::ios::sync_with_stdio(false);
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cin.tie(nullptr);
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cin >> t >> n >> s;
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s = ' ' + s;
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len[0] = 1;
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for (int i = 1; i <= n; i++) {
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len[s[i] == '1' ? ++cnt : cnt]++;
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}
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for (int i = 1; i <= cnt; i++) {
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if (i % 2 == 1) {
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ans += static_cast<long long>(cnt_even) * len[i];
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cnt_even += len[i - 1];
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} else {
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ans += static_cast<long long>(cnt_odd) * len[i];
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cnt_odd += len[i - 1];
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}
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}
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for (int i = 1; i <= cnt; i++) {
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if (len[i - 1] > 1 && len[i] > 1) {
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ans += static_cast<long long>(len[i - 1] - 1) * (len[i] - 1);
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}
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}
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cout << ans << endl;
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return 0;
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}
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