2026年GPLT天梯赛总结
从前到后a了11个题，刚好175铜，说说总结。这是我第一次国奖（以及第一次写博客），祝贺一下，去年也来打了，但是那时候整个人的状态都不好，好像只有6、70分，今年连规则都忘了，但状态不错（可能是我睡到10点才醒缘故？），本来也没打算拿奖，打算打完就走人。但越到后面状态越好，想拼一下，可惜L2差一题，时间来不及了，连样例的图都没画出来（我可能就能看出来可能有环了）。感觉天梯赛的难度主要在题量和L3上，哪怕前面的题简单也来不及做L3，附上我的代码，随便看看吧。
L1
基本没什么好说的
p1
#include<bits/stdc++.h>
using namespace std;
using ll = long long;
const int mod = 1000000007;
const int N = 1000005;
int main(){
ios::sync_with_stdio(false);
cin.tie(0); cout.tie(0);
cout << "Building the Future, One Line of Code at a Time.";
return 0;
}
p2
#include<bits/stdc++.h>
using namespace std;
using ll = long long;
const int mod = 1000000007;
const int N = 1000005;
int main(){
ios::sync_with_stdio(false);
cin.tie(0); cout.tie(0);
int n; cin >> n;
cout << n * 15;
return 0;
}
p3
#include<bits/stdc++.h>
using namespace std;
using ll = long long;
const int mod = 1000000007;
const int N = 1000005;
int main(){
ios::sync_with_stdio(false);
cin.tie(0); cout.tie(0);
int a, b; cin >> a >>b;
cout << b - a << '\n';
if(b - a <= 0)cout << "hai sheng ma?";
else if(b - a <= 250)cout << "nin tai cong ming le!";
else cout << "jiu ting tu ran de...";
return 0;
}
p4
#include<bits/stdc++.h>
using namespace std;
using ll = long long;
const int mod = 1000000007;
const int N = 1000005;
int main(){
ios::sync_with_stdio(false);
cin.tie(0); cout.tie(0);
int n; cin >> n;
int ans = 0;
while(n--){
int t; cin >> t;
if(t < 1700)ans++;
}
cout << ans;
return 0;
}
p5
#include<bits/stdc++.h>
using namespace std;
using ll = long long;
const int mod = 1000000007;
const int N = 1000005;
int main(){
ios::sync_with_stdio(false);
cin.tie(0); cout.tie(0);
int n; cin >> n;
set<int> s0, s1;
for(int i = 0; i < n; i++){
int no, tmp; cin >> no >> tmp;
if(tmp == 1){
if(s0.count(no))s0.erase(no);
s1.insert(no);
}else if(tmp == 0 && s1.count(no) == 0){
s0.insert(no);
}
}
vector<int> ans;
for(auto i : s0){
ans.push_back(i);
}
if(s0.size() == 0)cout << "NONE";
else {
for(int i = 0; i < (int)ans.size(); i++){
cout << ans[i];
if(i != (int)ans.size() - 1)cout << ' ';
}
}
return 0;
}
比赛时猪脑过载想不出来怎么遍历set比较方便输出，最后开了个vector复制了一遍，改成下面更好：
bool first = 1;
for (int x : good) {
if (!first) cout << ' ';
first = 0;
cout << x;
}
p6
#include<bits/stdc++.h>
using namespace std;
using ll = long long;
const int mod = 1000000007;
const int N = 1000005;
int main(){
ios::sync_with_stdio(false);
cin.tie(0); cout.tie(0);
vector<int> ans;
for(int i = 0; i < 11; i++){
string s;
getline(cin, s);
ans.push_back(s.size());
}
for(int i = 0; i< 11; i++){
cout << ans[i];
}
return 0;
}
p7
#include<bits/stdc++.h>
using namespace std;
using ll = long long;
const int mod = 1000000007;
const int N = 1000005;
int main(){
ios::sync_with_stdio(false);
cin.tie(0); cout.tie(0);
int n; cin >> n;
ll mmax = INT_MIN, mmin = INT_MAX, aver = 0;
vector<ll> num(n);
for(int i = 0; i < n; i++){
cin >> num[i];
aver += num[i];
mmax = max(num[i], mmax);
mmin = min(num[i], mmin);
}
vector<int> ans;
aver /= n;
for(int i = 0; i < n; i++){
if(num[i] > 2 * aver)ans.push_back(i + 1);
}
cout << mmax << ' ' << mmin << ' ' << aver << '\n';
if(ans.size() == 0)cout << "Normal";
else {
for(int i = 0; i < (int)ans.size(); i++){
cout << ans[i];
if(i != (int)ans.size() - 1)cout << ' ';
}
}
return 0;
}
# L2
不难只考了基本的算法，反映出我的C++基本功不扎实，字符串等于没练，今年这么简单的字符串题应该很快就能秒的，还有就是一些常见函数的返回值和参数都不知道。
p8
#include<bits/stdc++.h>
using namespace std;
using ll = long long;
const int mod = 1000000007;
const int N = 1000005;
int main(){
ios::sync_with_stdio(false);
cin.tie(0); cout.tie(0);
int n; cin >> n;
string s; cin >> s;
for(int i = 0; i < n; i++){
int opt; cin >> opt;
if(opt == 1){
string tmp; cin >> tmp;
vector<int> vpos;
size_t pos = 0;
for(int j = 0; j < 3; j++){
pos = s.find(tmp, pos);
if(pos == string::npos)break;
vpos.push_back(pos);
pos ++;
}
if(vpos.size() == 0)cout << -1 << '\n';
else {
for(int j = 0; j < (int)vpos.size(); j++){
cout << vpos[j];
if(j != (int)vpos.size() - 1)cout << ' ';
}cout << '\n';
}
}
else if(opt == 2){
int pos; cin >> pos;
string tmp; cin >> tmp;
s.insert(pos, tmp);
cout << s << '\n';
}
else {
int l, r; cin >> l >> r;
for(int j = 0; j < (r - l + 1) / 2; j++){
swap(s[l + j], s[r - j]);
}
cout << s << '\n';
}
}
return 0;
}
同样猪脑过载，赛时被find函数究竟返回什么类型憋了很久
p9
没话说了，感觉自己好蠢，真的想不出来更好的方法了
#include<bits/stdc++.h>
using namespace std;
using ll = long long;
const int mod = 1000000007;
const int N = 1000005;
int main(){
ios::sync_with_stdio(false);
cin.tie(0); cout.tie(0);
int n, t; cin >> n >> t;
vector<int> vn(n + 1);
vector<bool> vis(n + 1);
vector<int> ans;
int sum = 0, m = 0;
for(int i = 1; i <= n; i++){
cin >> vn[i];
if(vn[i] <= t){
ans.push_back(i);
vis[i] = true;
}
else {
sum += vn[i];
m++;
}
}
bool f = 1;
while(ans.size() < n){
t = sum / m;
// cout << t << '\n';
sum = 0;
m = 0;
if(!f){
for(int i = 1; i <= n; i++){
if(!vis[i]){
if(vn[i] <= t){
ans.push_back(i);
vis[i] = true;
}
else {
sum += vn[i];
m++;
}
}
}
}
else {
for(int i = n; i >= 1; i--){
if(!vis[i]){
if(vn[i] <= t){
ans.push_back(i);
vis[i] = true;
}
else {
sum += vn[i];
m++;
}
}
}
}
f = !f;
}
for(int i = 0; i < n; i++){
cout << ans[i] ;
if(i != (int)ans.size() - 1)cout << ' ';
}
return 0;
}
p10
忘了对于自定义类型究竟怎么使用upper_bound()，最开始重载了三个参数为int的比较运算符，还是报错，想了好长时间，最后手写二分
- upper_bound()可以给第四个参数传lambda表达式比较自定义类和int
auto it = upper_bound(vi.begin(), vi.end(), tmp,
[](int val, const num& x) {
return val < x.data;
}
);
- 也可以重载参数为该类的小于号，upper_bound()第三个参数改为该类
auto it = upper_bound(vi.begin(), vi.end(), num{0, tmp});
#include<bits/stdc++.h>
using namespace std;
using ll = long long;
const int mod = 1000000007;
const int N = 1000005;
class num{
public:
int no, data;
};
int main(){
ios::sync_with_stdio(false);
cin.tie(0); cout.tie(0);
int n; cin >> n;
vector<int> pos;
vector<num> vi(n);
int mmax = 0;
for(int i = 0; i < n; i++){
cin >> vi[i].data;
vi[i].no = i + 1;
if(vi[i].data > mmax){
mmax = vi[i].data;
pos.clear();
pos.push_back(i + 1);
}else if(vi[i].data == mmax)pos.push_back(i + 1);
}
for(int i = 0; i < (int)pos.size(); i++){
cout << pos[i];
if(i != (int)pos.size() - 1) cout << ' ';
}cout << '\n';
int m; cin >> m;
sort(vi.begin(), vi.end(), [](const num& a, const num& b){
return tie(a.data, a.no) < tie(b.data, b.no);
});
for(int i = 0; i < m; i++){
int tmp; cin >> tmp;
int l = 0, r = n - 1;
while(l < r){
int mid = (l + r) >> 1;
if(vi[mid].data > tmp){
r = mid;
}else {
l = mid + 1;
}
}
if(vi[n - 1].data <= tmp)cout << 0 << '\n';
else cout << vi[l].no << '\n';
}
return 0;
}
p11
递归会爆栈，必须改栈
#include<bits/stdc++.h>
using namespace std;
using ll = long long;
const int mod = 1000000007;
const int N = 1000005;
vector<pair<int, int>> kid;
int dfs(int idx, map<int, vector<pair<int, int>>>& miv, int res){
if(miv[idx].size() == 0){
kid.push_back({idx, res});
return res;
}
int mmax = 0;
for(int i = 0; i < (int)miv[idx].size(); i++){
mmax = max(dfs(miv[idx][i].first, miv, min(res, miv[idx][i].second)), mmax);
}
return mmax;
}
int main(){
ios::sync_with_stdio(false);
cin.tie(0); cout.tie(0);
int n; cin >> n;
map<int, vector<pair<int, int>>> miv;
for(int i = 1; i <= n - 1; i++){
int f, data; cin >> f >> data;
// miv[i].push_back({f, data});
miv[f].push_back({i, data});
}
int mmax = 0;
stack<int> si, sres;
si.push(0);
sres.push(INT_MAX);
while(!si.empty()){
int idx = si.top();
int curmax = sres.top();
si.pop();
sres.pop();
if(miv[idx].size() == 0){
kid.push_back({idx, curmax});
mmax = max(mmax, curmax);
}
else {
for(int i = 0; i < (int)miv[idx].size(); i++){
si.push(miv[idx][i].first);
sres.push(min(curmax, miv[idx][i].second));
}
}
}
cout << mmax << '\n';
vector<int> ans;
for(int i = 0; i < (int)kid.size(); i++){
if(kid[i].second == mmax)ans.push_back(kid[i].first);
}
sort(ans.begin(), ans.end());
for(int i = 0; i < (int)ans.size(); i++){
cout << ans[i];
if(i != (int)ans.size() - 1)cout << ' ';
}
return 0;
}
后面的p12因只有20分钟了，没读清题，甚至没看好数据，不知道有环，while死活退不出来，赛后仔细看了数据轻轻的四了...
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