Statistics from a Large Sample
给一个数组, i位上的数n表示n个i, 求min,max,mean, median,mode. 这里只有中位数需要考虑下, 因为数组是频率数组, 所以用两个指针, 辗转相减, 就能找到中间的两个数.
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class Solution { public double[] sampleStats(int[] count) { int min = Integer.MAX_VALUE; int max = Integer.MIN_VALUE; int maxValue = 0; int mode = 0; double avg = 0.0; int c = 0; for(int i = 0; i < count.length; i++) { if(count[i] == 0) continue; min = Math.min(min, i); max = Math.max(max, i); avg += count[i] * i; c += count[i]; if(maxValue < count[i]){ maxValue = count[i]; mode = i; } } avg /= (double)c; /*median*/ int left = 0; int right = count.length - 1; while( left < right) { if(count[left] == 0) { left++; } else if(count[right] == 0) { right--; } else if(count[left] < count[right]) { count[right] -= count[left]; left++; } else if(count[left] > count[right]){ count[left] -= count[right]; right--; } else { left++; right--; } } double median = 0.0; median = (double)(right + left) / 2.0; return new double[]{min, max, avg, median, mode}; } } |