剑指offer读书笔记第五章，优化时间和空间效率

int maxSubArray(int A[], int n) {

        int curSum = 0;
        int maxSum = A[0];

        for(int j = 0; j < n; j  ) {
            if(curSum >= 0)  {
                curSum  = A[j];
            }
            else {
                curSum = A[j];
            }
            if(curSum > maxSum) {
                maxSum = curSum;
            }
        }
        return maxSum;
    }

#include <iostream>
#include <vector>
#include <map>
#include <unordered_map>
#include <set>
#include <unordered_set>
#include <queue>
#include <stack>
#include <string>
#include <climits>
#include <algorithm>
#include <sstream>
#include <functional>
#include <bitset>
#include <numeric>
#include <cmath>
#include <regex>
#include <iomanip>
#include <cstdlib>
#include <ctime>

using namespace std;

bool cmp(int a, int b)
{
    string ab = to_string(a)   to_string(b);
    string ba = to_string(b)   to_string(a);
    return ab < ba;
}
class Solution 
{
public:
    string PrintMinNumber(vector<int> n) 
    {
        sort(n.begin(), n.end(), cmp);

        string res = "";
        for (int i : n)
            res  = to_string(i);
        return res;
    }
};

#include <iostream>
#include <vector>
#include <map>
#include <unordered_map>
#include <set>
#include <unordered_set>
#include <queue>
#include <stack>
#include <string>
#include <climits>
#include <algorithm>
#include <sstream>
#include <functional>
#include <bitset>
#include <numeric>
#include <cmath>
#include <regex>
#include <iomanip>
#include <cstdlib>
#include <ctime>

using namespace std;

class Solution 
{
public:
    int MMD = 1000000007;
    int mergeSort(vector<int>& a, vector<int>& tmp, int beg, int end)
    {
        if (beg >= end)
            return 0;
        else
        {
            int mid = (end - beg) / 2   beg;
            long long left = (mergeSort(a, tmp, beg, mid)) % MMD;
            long long right = (mergeSort(a, tmp, mid   1, end)) % MMD;
            long long count = 0;
            int i = beg, j = mid   1, k = beg;
            while (i <= mid && j <= end)
            {
                if (a[i] <= a[j])
                    tmp[k  ] = a[i  ];
                else
                {
                    tmp[k  ] = a[j  ];
                    count  = (mid - i   1);
                }
            }

            while (i <= mid)
                tmp[k  ] = a[i  ];
            while (j <= end)
                tmp[k  ] = a[j  ];

            for (int i = beg; i <= end; i  )
                a[i] = tmp[i];

            long long res = (left   right   count) % MMD;
            return (int)res;

        }
    }

    int InversePairs(vector<int> a) 
    {
        vector<int> tmp(a);
        return mergeSort(a, tmp, 0, a.size() - 1);
    }
};