John ' s business

There are n cities on a axis, numbers from 0 ~ n-1. John intends to did business in this N cities, he was interested in Armani ' s shipment. Each of the city has a price for these goods prices [i]. For City X, John can-buy-goods from the "city numbered" from X-k to X + K, and sell them to City X. We want to know how much of John can earn at most.

Considerations
Prices.length The range is [2, 100000], K <= 100000.

Examples
Given prices = [1, 3, 2, 1, 5], k = 2, return [0, 2, 1, 0, 4].

Explanation:
i = 0, John can go to the city 0 ~ 2. He can don't make money because the "prices in City 1" and "City 2 are both higher than" the price of city 0, which is, ans[0] = 0;
i = 1, John can go to the city 0~3. He can buy from City 0 or City 3 to earn the largest price difference. That is, ans[1] = 2.
i = 2, John can go to the city 0~4. Obviously, he can earn of the largest price difference by buying to City 3. That is, ans[2] = 1.
i = 3, John can go to the city 1~4. He can don't make money cause City 3 has the lowest price. That is, ans[3] = 0.
i = 4, John can go to the city 2~4. He can earn the "largest price difference" by buying to City 3. That is, ans[4] = 4.

Given prices = [1, 1, 1, 1, 1], k = 1, return [0, 0, 0, 0, 0]

Explanation: All cities are of the same price, and so
John can don't make, which is, all ans are 0.

For the first time, TLE

#ifndef c751_h #define C751_H #include <iostream> #include <vector> using namespace std; Class Solution {public:/** * @param a:the prices [i] * @param k: * @return: the ANS array */ve
        Ctor<int> Business (vector<int> &a, int k) {//Write your code here int len = A.size ();
        vector<int> Res (len, 0);
        int min = Int_max;
        for (auto c:a) {if (min > c) min = C;
            } if (k >= len) {for (auto &c:a) c-= min;
        return A;
            for (int i = 0; i < len; ++i) {int value = Int_min;
            if (i-k <= 0 && i + K >= len-1) {value = a[i]-min; else if (i-k <= 0 && i + K < len-1) {for (int j = 0; J <= i + K;
        ++J) {            Value = Maxval (value, A[i]-a[j]);  ' Else if ' (i-k>0 && i + k >= len-1) {for (int j = I-k; J < Len;
                ++J) {value = Maxval (value, A[i]-a[j]);
                    } else {for (int j = i-k; J <= i + K; ++j) {
                Value = Maxval (value, A[i]-a[j]);
        }} Res[i] = value;
    return res;
    int maxval (int a, int b) {return a>b? a:b;
}
}; #endif

The topic is essentially to find the minimum value min on the interval [i-k,i+k] for position I, and to take the new value a[i]-min. The
can take advantage of line-segment trees:

#ifndef c751_h #define C751_H #include <iostream> #include <vector> using namespace std;
    Class segmentnode{Public:int start, end, Min;
    Segmentnode *left, *right;
        Segmentnode (int start, int end, int min) {this->start = start;
        This->end = end;
        this->min;
    This->left = This->right = NULL;
}
}; Class Solution {public:/** * @param a:the prices [i] * @param k: * @return: the ANS array */ve
        Ctor<int> Business (vector<int> &a, int k) {//Write your code here int len = A.size ();
        vector<int> Res (len, 0);
        Segmentnode *root = Build (A, 0, len-1);
            for (int i = 0; i<len; ++i) {int start = I-k;
            int end = i + K;
            Fixed interval range if (Start < 0) start = 0;
            If (end >= len) end = len-1;
   Res[i] = a[i]-query (root, start, end);     return res;  //Query segment tree minimum value int query (segmentnode *root, int start, int end) on interval [start,end] {if (Start > End | |
        !root) return 0;
        Segmentnode *node = root;
        if (start = = Node->start&&end = node->end) return node->min;
        if (start >= node->right->start) return to query (Node->right, start, end);
        else if (end <= node->left->end) return query (Node->left, start, end); else {return minval query (Node->left, start, node->left->end), query (Node->right, NODE-&G
        T;right->start, end)); }//Build line segment tree, node contains minimum value within interval segmentnode *build (vector<int> &a, int start, int end) {if STA
        RT > end] Return NULL;
        Segmentnode *node = new Segmentnode (start, end, Int_max);
        if (start = = end) Node->min = A[start];
  else {          Node->left = Build (A, start, (start + end)/2);
            Node->right = Build (A, [start + end]/2 + 1, end);
        Node->min = Minval (Node->left->min, node->right->min);
    } return node;
    int minval (int a, int b) {return a < b a:b;
}
}; #endif