南外集训 Day 11

The eleventh day of intensive training at Nanjing Foreign Language School.
第一题暴力
第二题还是暴力
第三题思路是对的，但是解法是错的

#include <bits/stdc++.h>
using namespace std;
int a[505000], b[505000], n, ans;
int main() {
    cin >> n;
    for (int i = 1; i <= n; i++) {
        cin >> a[i];
    }
    for (int i = 1; i <= n; i++) {
        cin >> b[i];
    }
    int l = 1, r = n;
    sort(a + 1, a + 1 + n);
    sort(b + 1, b + 1 + n);
    while (l <= n && b[r] > 0) {
        if (a[l] + b[r] < 0) {
            ans++;
            l++;
        }
        r--;
    }
    l = 1, r = n;
    while (l <= n && a[r] > 0) {
        if (a[r] + b[l] < 0) {
            ans++;
            l++;
        }
        r--;
    }
    cout << ans;
    return 0;
}

第四题模拟，判断有误，导致90

#include <bits/stdc++.h>
using namespace std;
int n;
string a;
int main() {
    cin >> n;
    while (n) {
        cin >> a;
        int len = a.size();
        int k = 0;
        bool r = false;
        for (int i = 0; i < len; i++) {
            if (a[i] != &#039;:&#039; && r == false) {
                r = true;
                k++;
            } else if (a[i] == &#039;:&#039;) {
                r = false;
            }
        }
        k = 8 - k;
        for (int i = 0; i < len; i++) {
            if (a[i] == &#039;:&#039; && a[i + 1] == &#039;:&#039;) {
                bool bb = false;
                if (i == 0) {
                    bb = true;
                }
                if (i == len - 2) {
                    k--;
                }
                if (k == 1 && i == 0) {
                    cout << "0000:";
                    k = 0;
                }
                while (k) {
                    if (k == 1) {
                        cout << ":0000:";
                    } else if (bb == true) {
                        cout << "0000";
                        bb = false;
                    } else {
                        cout << ":0000";
                    }
                    k--;
                }
                i = i + 2;
            }
            int x = 0;
            if (a[i - 1] == &#039;:&#039; || i == 0) {
                for (int j = 0; j < 4; j++) {
                    if (a[i + j] == &#039;:&#039; || i + j == len) {
                        x = 4 - j;
                        break;
                    }
                }
                for (int j = 1; j <= x; j++) {
                    cout << "0";
                }
                for (int j = 0; j <= 3 - x; j++) {
                    cout << a[i + j];
                }
                i += 3 - x;
            } else {
                cout << a[i];
            }
        }
        cout << endl;
        n--;
    }
    return 0;
}