数据离散化

#include <iostream>
#include <cstdio>
#include <algorithm>

using namespace std;

int a[1005], b[1005], sub[1005]; //a[n]是即将被离散化的数组，b[n]是a[n]的副本，sub用于排序去重后提供离散化后的值

int main () {
    int n;
    cin >> n;
    for(int i = 0; i < n; i++) {
        scanf("%d", &a[i]);
        sub[i] = a[i];
        b[i] = a[i];
    }
    sort(sub, sub + n);
    int size = unique(sub, sub + n) - sub; //此处为数组去重，并获取去重后的长度
    for(int i = 0; i < n; i++) {
           a[i] = lower_bound(sub, sub + size, a[i]) - sub; //即a[i]为b[i]离散化后对应的值，a[i]中的值是sub[i]中的下标
    }
    for(int i = 0; i < size; i++) {
        printf("%d%c", sub[i], " \n"[i == size - 1]);
    }
    for(int i = 0; i < n; i++) {
        printf("%d%c", a[i], " \n"[i == n - 1]);
    }
    return 0;
}