Say you have an array for which the ith element is the price of a given stock on day i.
Design an algorithm to find the maximum profit. You may complete as many transactions as you like (ie, buy one and sell one share of the stock multiple times). However, you may not engage in multiple transactions at the same time (ie, you must sell the stock before you buy again).
» Solve this problem
如果当前值高于买入值,那么就卖出,同时买入今天的股票。
如果当前值低于买入值,那么就放弃之前的股票,同时买入今天的股票。
举例:
1 3 9 7 8
第1天,买入1;
第2天,3>1,卖出,获利2,并买入3;
第3天,9>3,卖出,获利6,并买入9;
第4天,7<9,放弃9,买入7;
第5天,8>7,卖出,获利1,结束。
总获利:2+6+1 = 9。
class Solution {
public:
int maxProfit(vector<int> &prices) {
// Start typing your C/C++ solution below
// DO NOT write int main() function
int profit = 0, value = 0;
if (prices.size() == 0) {
return profit;
}
value = prices[0];
for (int i = 1; i < prices.size(); i++) {
if (prices[i] < value) {
value = prices[i];
}
else {
profit += prices[i] - value;
value = prices[i];
}
}
return profit;
}
};