abc098D Xor Sum 2(two point)
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2022-06-22 12:06:55
题意 "题目链接" 给出一个序列,求出有多少区间满足$A[l] \oplus A[l+1] \oplus \dots \oplus A[r] = A[l] + A[l + 1] +\dots+ A[r]$ Sol 一个区间能满足要求一定是所有bit上最多只有一个1 这玩意儿显然有单调性,two po ......
题意
给出一个序列,求出有多少区间满足\(a[l] \oplus a[l+1] \oplus \dots \oplus a[r] = a[l] + a[l + 1] +\dots+ a[r]\)
sol
一个区间能满足要求一定是所有bit上最多只有一个1
这玩意儿显然有单调性,two point扫一遍
#include<cstdio> #define ll long long using namespace std; const int maxn = 2e5 + 10; inline int read() { char c = getchar(); int x = 0, f = 1; while(c < '0' || c > '9') {if(c == '-') f = -1; c = getchar();} while(c >= '0' && c <= '9') x = x * 10 + c - '0', c = getchar(); return x * f; } int n, a[maxn]; main() { n = read(); for(int i = 1; i <= n; i++) a[i] = read(); ll l = 1, sxor = 0, sum = 0, ans = 0; for(int i = 1; i <= n; i++) { sum += a[i]; sxor ^= a[i]; while(sxor != sum && (l < i)) sum -= a[l], sxor ^= a[l++]; ans += i - l + 1; } printf("%lld", ans); return 0; }