请问为什么第一个代码能过第二个就过不了，两个都能过样例

#include <bits/stdc++.h>
using namespace std;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0), cout.tie(0);
    int n, num, score;
    string name;
    map<string, int> mp;
    map<string, int>::iterator it;
    cin >> n;
    for (int i = 1; i <= n; i++) {
        cin >> num;
        switch (num) {
            case 1:
                cin >> name >> score;
                mp[name] = score;
                cout << "OK" << endl;
                break;
            case 2:
                cin >> name;
                it = mp.find(name);
                if (it != mp.end()) {
                    cout << mp[name] << endl;
                } else {
                    cout << "Not found" << endl;
                }
                break;
            case 3:
                cin >> name;
                it = mp.find(name);
                if (it != mp.end()) {
                    mp.erase(it);
                    cout << "Deleted successfully" << endl;
                } else {
                    cout << "Not found" << endl;
                }
                break;
            case 4:
                cout << mp.size() << endl;
                break;
        }
    }
    // cout.flush();
    // system("pause");
    return 0;
}

#include <bits/stdc++.h>
using namespace std;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0), cout.tie(0);
    int n, num, score;
    string name;
    map<string, int> mp;
    map<string, int>::iterator it;
    cin >> n;
    for (int i = 1; i <= n; i++) {
        cin >> num;
        switch (num) {
            case 1:
                cin >> name >> score;
                mp.insert(make_pair(name, score));
                cout << "OK" << endl;
                break;
            case 2:
                cin >> name;
                it = mp.find(name);
                if (it != mp.end()) {
                    cout << it->second << endl;
                } else {
                    cout << "Not found" << endl;
                }
                break;
            case 3:
                cin >> name;
                it = mp.find(name);
                if (it != mp.end()) {
                    mp.erase(it);
                    cout << "Deleted successfully" << endl;
                } else {
                    cout << "Not found" << endl;
                }
                break;
            case 4:
                cout << mp.size() << endl;
                break;
        }
    }
    // cout.flush();
    // system("pause");
    return 0;
}