【字符串处理】— 最大子序列和

package base;

//最大子序列和，包括全负数情况。 思想是依次遍历数组，如何本次的和大于上次的和 则本次大，并且如果本次和为0 则
//开始指针移动到i++位置
public class MaxSubSeq {

    public static void main(String[] args) {
        
        MaxSubSeq mss = new MaxSubSeq();
        System.out.println("The max is = " + mss.getMaxSubSeq(new int[]{-1,-3,-21,-3,-5,-2}));
    }
    
    private int getMaxSubSeq(int[] array){
        
        int arraySize = array.length;
        int start = 0;            //开始指针
        int finish = 0;            //结束指针
        int sum = 0;            //最大累加和
        int max = 0;            //上一次的累加和
        int _max = Integer.MIN_VALUE;            //系统最小负值（如果和值为负则为最大值）
        int _maxI = 0;                            //全负值情况坐标
        for(int i=0;i<arraySize;i++){
            sum += array[i];
            if(_max < array[i]){
                _max = array[i];
                _maxI = i;
            }
            if(sum <= 0){
                start = i+1;
                sum = 0;
            }
            if(sum > max){
                max = sum;
                finish = i;
            }
        }
        if(_max < 0){
            System.out.println("The start is = " + _maxI + " and The end is = " + _maxI);
            return _max;
        }
        System.out.println("The start is = " + start + " and The end is = " + finish);
        return max;
    }
}