1547D - Co-growing Sequence

// Problem: D. Co-growing Sequence
// Contest: Codeforces - Codeforces Round #731 (Div. 3)
// URL: https://codeforces.com/problemset/problem/1547/D
// Memory Limit: 512 MB
// Time Limit: 2000 ms
// 2022-02-19 15:00:11
// 
// Powered by CP Editor (https://cpeditor.org)

#include<bits/stdc++.h>
using namespace std;

#define rep(i,l,r) for(int i=(l);i<=(r);i++)
#define per(i,l,r) for(int i=(l);i>=(r);i--)
#define ll long long
#define pii pair<int, int>
#define mset(s,t) memset(s,t,sizeof(t))
#define mcpy(s,t) memcpy(s,t,sizeof(t))
#define fir first
#define pb push_back
#define sec second
#define sortall(x) sort((x).begin(),(x).end())
inline int read () {
    int x = 0, f = 0;
    char ch = getchar();
    while (!isdigit(ch)) f |= (ch=='-'),ch= getchar();
    while (isdigit(ch)) x = x * 10 + ch - '0', ch = getchar();
    return f?-x:x;
}
template<typename T> void print(T x) {
    if (x < 0) putchar('-'), x = -x;
    if (x >= 10) print(x/10);
    putchar(x % 10 + '0');
}
int n;
int a[200005];
int b[200005];
void solve() {
    cin >> n;
    for (int i = 1; i <= n; i ++)
        cin >> a[i];
    b[1] = 0;
    memset(b, 0, sizeof b);
    for (int i= 2; i <= n; i ++) {
        int ans = 0;
        for (int j= 0; j <= 30; j ++) {
            if (!(a[i] >> j & 1) && ((a[i - 1] ^ b[i - 1]) >> j & 1)) {
                b[i] += pow(2, j);
            }
        }
    }
    for (int i = 1;  i<= n; i ++)
        cout << b[i] << " \n"[i == n];
}
int main () {
    int t;
    cin >> t;
    while (t --) solve();
    return 0;
}

通过让首位最小，然后后面的就确定了。整个序列一定是最小的且唯一的