【leetcode】121. 买卖股票的最佳时机

int maxProfit(int* prices, int pricesSize){
    int sum=0, i, max=0;
    for(i=1; i<pricesSize; i++){
        sum += prices[i]-prices[i-1];
        if(sum<0) sum=0;
        if(sum>max) max=sum;
    }
    return max;
}