排序练习题（六）：相邻两数最大差值

public class Gap {
    public int maxGap(int[] A, int n) {
        // write code here
        if(null == A ||n<2) return 0;
        int min=Integer.MAX_VALUE;
        int max=Integer.MIN_VALUE;
        for(int i=0;i<n;i++){
            if(A[i]>max) max=A[i];
            if(A[i]<min) min=A[i];
        }
        if(min==max) return 0;
        boolean[] hasNum =new boolean[n+1];
        int[]maxs=new int[n+1];
        int[] mins=new int[n+1];
        for(int i=0;i<n;i++){
            int bid=bucket(A[i],n,min,max);
            maxs[bid]=hasNum[bid]?Math.max(maxs[bid],A[i]):A[i];
            mins[bid]=hasNum[bid]?Math.min(mins[bid],A[i]):A[i];
            hasNum[bid]=true;
        }
        int res=0;
        int lastMax=0;
        int i=0;
        while(i<=n){
            if(hasNum[i++]){
                lastMax = maxs[i-1];
                break;
            }
        }
        for(;i<=n;i++){
            if(hasNum[i]){
                res=Math.max(res,mins[i]-lastMax);
                lastMax=maxs[i];
            }
        }
        return res;
         
    }
    public int bucket(long num,long length,long min,long max){
        return (int)((num-min)*length/(max-min));
    }
}