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;
}