LeetCode 1187. 使数组严格递增

tle 但是我好开心啊（真）

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

int srh(vector<int>& arr1, vector<int>& arr2, int a, int b)
{//搜索改完，搜完，一定要改回来再搜，保持之后的人还是原数组
    if(a>=arr1.size()) return 0;
    int ans = arr2.size()+1;
    int j = b;//先搜索换的部分
    for(; j < arr2.size(); j++)
    {//找到比前一个数字大一点的那个
        if(arr2[j] > arr1[a-1]) break;
    }
    if(j < arr2.size()) 
    {//如果存在大一点的那个，就换然后搜
        int t = arr1[a];
        arr1[a] = arr2[j];
        ans = srh(arr1, arr2, a+1, j+1)+1;
        arr1[a] = t;//把数字换回去
    }//然后搜不换的情况（如果不换也暂时可以的话）
    if(arr1[a] > arr1[a-1]) ans = min(ans,srh(arr1, arr2, a+1, b));
    return ans;
}

int makeArrayIncreasing(vector<int>& arr1, vector<int>& arr2) {
    sort(arr2.begin(), arr2.end());
    vector<int>::iterator new_end = unique(arr2.begin(), arr2.end());//"删除"相邻的重复元素
    arr2.erase(new_end, arr2.end());//删除(真正的删除)重复的元素
    int t = arr1[0];
    arr1[0] = arr2[0];
    int ans = srh(arr1, arr2, 1, 1)+1;
    arr1[0] = t;
    ans = min(ans, srh(arr1, arr2, 1, 0));
    if (ans > arr2.size()) ans = -1;
    return ans;
}

int main(int argc, char const *argv[])
{
    int a[10] = {5,16,19,2,1,12,7,14,5,16};
    int b[15] = {6,17,4,3,6,13,4,3,18,17,16,7,14,1,16};
    vector<int> arr1(a, a+10);
    vector<int> arr2(b, b+15);
    int ans = makeArrayIncreasing(arr1, arr2);
    cout<<ans<<endl;
    return 0;
}

dp的解法

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

int makeArrayIncreasing(vector<int>& arr1, vector<int>& arr2) {
    sort(arr2.begin(), arr2.end());
    vector<int>::iterator new_end = unique(arr2.begin(), arr2.end());//"删除"相邻的重复元素
    arr2.erase(new_end, arr2.end());//删除(真正的删除)重复的元素
    int n = arr1.size();
    int m = arr2.size();
    int ans = m+1;
    int dp[2020][2020];
    memset(dp, 0x3f, sizeof(dp));
    dp[0][0] = 0;
    for (int j = 1; j <= m; ++j)
    {
        dp[0][j] = 1;
    }
    for (int i = 1; i < n; ++i)
    {
        if (arr1[i-1] < arr1[i])
        {//本步不进行换 上一步也不换
            dp[i][0] = min(dp[i][0], dp[i-1][0]);
        }
        int l = 0;

        while(l < m && arr2[l] < arr1[i]) l++; 
        for (int k = 1; k <= l; ++k)
        {//本步不进行换 上一步换
            dp[i][0] = min(dp[i][0], dp[i-1][k]);
        }

        l = 0;
        while(l < m && arr2[l] <= arr1[i-1]) l++;
        for (int j = l+1; j <= m; ++j)
        {//本步换，上一步不换
            dp[i][j] = min(dp[i][j], dp[i-1][0]+1);
        }

        for (int j = 2; j <= m; ++j)
        {//本步换，上一步也换
            dp[i][j] = min(dp[i][j],dp[i-1][j-1]+1);
        }
    }
    for (int j = 0; j <= m; ++j)
    {
        ans = min(ans, dp[n-1][j]);
    }
    if (ans > m) ans = -1;
    return ans;
}

int main(int argc, char const *argv[])
{
    int a[12] = {23,10,9,12,3,14,21,16,7,10,17,12};
    int b[19] = {6,5,0,15,2,17,4,11,6,5,8,15,10,1,20,11,14,13,8};
    vector<int> arr1(a, a+12);
    vector<int> arr2(b, b+19);
    int ans = makeArrayIncreasing(arr1, arr2);
    cout<<ans<<endl;
    return 0;
}