洛谷P10904挖矿

#include<bits/stdc++.h>
using namespace std;
int n, m;
const int N = 2000010;
int l[N], r[N];
int cnt;
int main(){cin >> n >> m;for(int i = 1; i <= n; i++){int x; cin >> x;if(x > 0){r[x]++;}else if(x < 0){l[-x]++;}else cnt = 1;}for(int i = 1; i < N; i++){l[i] += l[i - 1];r[i] += r[i - 1];}int ans = 0;for(int i = 0; i <= m; i++){int ll = l[i];if(m - 2 * i > 0){ll += r[m - 2 * i];}ans = max(ans, ll);int rr = r[i];if(m - 2 * i > 0){rr += l[m - 2 * i];}ans = max(ans, rr);}cout << ans + cnt << endl;return 0;
} 

洛谷P

#include<bits/stdc++.h>
using namespace std;
int n;
bool check(string a, int cnt1, int cnt2){int l = cnt1, r = a.length() - 1 - cnt2;while(l < r){if(a[l] != a[r])return false;l++, r--;}return true;
}
bool check2(string b, string c){if(b.size() < c.size())return false;for(int i = c.size() - 1, j = b.size() - 1; i >= 0; i--, j--){if(c[i] != b[j])return false;} return true;
}
int main(){ios::sync_with_stdio(false);cin.tie(nullptr);cin >> n;while(n--){string a; cin >> a;int cnt2 = 0, cnt1 = 0;string b = "";while(a[a.length() - 1 - cnt2] == 'l' || a[a.length() - 1 - cnt2] == 'q' || a[a.length() - 1 - cnt2] == 'b'){b += a[a.length() - 1 - cnt2];cnt2++;}string c = "";while(a[cnt1] == 'l' || a[cnt1] == 'q' || a[cnt1] == 'b'){c += a[cnt1];cnt1++;}if(check(a, cnt1, cnt2) && check2(b, c))cout << "Yes" << endl;else cout << "No" << endl;}return 0;
}