Submission #236954

#TimeUsernameProblemLanguageResultExecution timeMemory
236954PeppaPigElection (BOI18_election)C++14
0 / 100
14 ms12800 KiB
#include <bits/stdc++.h> #define pii pair<int, int> #define x first #define y second using namespace std; const int N = 1 << 19; int n, q, ans[N]; class SegmentTree { private: int t[N << 1], lz[N << 1]; void push(int p, int l, int r) { if(lz[p]) { t[p] += lz[p]; if(l != r) lz[p << 1] += lz[p], lz[p << 1 | 1] += lz[p]; lz[p] = 0; } } template<typename T> void travel(int x, int y, const T &f, int p = 1, int l = 1, int r = n) { push(p, l, r); if(x > r || l > y) return; if(x <= l && r <= y) return f(p, l, r); int mid = (l + r) >> 1; travel(x, y, f, p << 1, l, mid), travel(x, y, f, p << 1 | 1, mid + 1, r); t[p] = min(t[p << 1], t[p << 1 | 1]); } public: void update(int x, int y, int k) { travel(x, y, [&](int p, int l, int r) { lz[p] += k, push(p, l, r); }); } int query(int x, int y, int ret = 0) { travel(x, y, [&](int p, int l, int r) { ret = min(ret, t[p]); }); return ret; } } tree; char S[N]; vector<pii> Q[N]; int main() { scanf("%d %s %d", &n, S + 1, &q); for(int i = 1, a, b; i <= q; i++) { scanf("%d %d", &a, &b); Q[b].emplace_back(a, i); } vector<int> stk; for(int i = 1; i <= n; i++) { if(S[i] == 'C') { if(!stk.empty()) tree.update(stk.back(), n, -1), stk.pop_back(); tree.update(i, n, 1); } else stk.emplace_back(i); for(pii p : Q[i]) { int lhs = tree.query(p.x, i) - tree.query(p.x - 1, p.x - 1); int rhs = (int)stk.size() - (lower_bound(stk.begin(), stk.end(), p.x) - stk.begin()); ans[p.y] = lhs + rhs; } } for(int i = 1; i <= q; i++) printf("%d\n", ans[i]); return 0; }

Compilation message (stderr)

election.cpp: In function 'int main()':
election.cpp:47:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d %s %d", &n, S + 1, &q);
     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
election.cpp:49:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d %d", &a, &b);
         ~~~~~^~~~~~~~~~~~~~~~~
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