lc1093.java

package code;
/*
 * 1093. Statistics from a Large Sample
 * 题意：从数组里统计出均值，最大，最小，中位数，众数
 * 难度：Medium
 * 分类：
 * 思路：
 * Tips：中位数记住可能是两个数的均值，可能是中间的一个数，用 pos/2 来处理
 */
public class lc1093 {
    public double[] sampleStats(int[] count) {
        double[] res = new double[5];
        res[0] = -1;
        res[1] = -1;
        int mode_num = 0;
        int count_num = 0;
        for (int i = 0; i < count.length ; i++) {
            if(res[0]==-1 && count[i]>0) res[0] = i;
            if(count[i]>0 && i>res[1]) res[1] = i;
            res[2] += count[i]*i;
            count_num += count[i];
            if(count[i]>mode_num) {
                res[4] = i;
                mode_num = count[i];
            }
        }
        int medium_pos1 = (count_num+1)/2;  //中位数
        int medium_pos2 = (count_num+2)/2;
        count_num = 0;
        for (int i = 0; i < count.length ; i++) {
            count_num += count[i];
            if(medium_pos1>0&&medium_pos1<=count_num) {
                res[3]+= i;
                medium_pos1 = -1;
            }
            if(medium_pos2>0&&medium_pos2<=count_num) {
                res[3]+= i;
                medium_pos2 = -1;
            }
        }
        res[2] = res[2]/count_num;
        res[3] = res[3]/2;
        return res;
    }
}