接雨水

public class  {
    
     * @param heights: an array of integers
     * @return: a integer
     */
    public int trapRainWater(int[] heights) {
        int sum=0;
        int index=0;
        int k=0;
        int mintemp=0;
        for(int i=0;i<heights.length-1;){
                if(heights[i]<=heights[i+1]){
                    i++;
                    continue;
                }
                else{
                    index=find(heights,heights[i],i+1);
                    if(index==0){
                        break;
                    }
                    k=i+1;
                    mintemp=Math.min(heights[i],heights[index]);
                    while(k<index){
                        sum+=mintemp-heights[k];
                        k++;
                    }
                    i=index;
                }
        }
        return sum;
    }
    
    public int find(int[] heights,int temp,int i){
        int max=0;
        int index=0;
        int k=i;
        int count=0;
        for(;i<heights.length;i++){
            if(i+1<heights.length&&heights[i]>=heights[i+1]){
                count++;
            }
            if(heights[i]>max){
                max=heights[i];
                index=i;
            }
            if(heights[i]>=temp){
                return i;
            }
        }
        if(count==heights.length-k){
            return 0;
        }
        return index;
    }
}