bzoj 1271
思路:因为被占奇数次的点只有一个, 那么我们可以将数轴分成两部分,奇数次点之前的前缀和为偶数,之后的前缀和为奇数,
然后就可以二分了。
#include<bits/stdc++.h> #define LL long long #define fi first #define se second #define mk make_pair #define pii pair<int,int> #define piii pair<int, pair<int,int> > using namespace std; const int N = 1e6 + 10; const int M = 10 + 7; const int inf = 0x3f3f3f3f; const LL INF = 0x3f3f3f3f3f3f3f3f; const int mod = 1e9 + 7; const double eps = 1e-6; LL s[N], t[N], d[N]; int n; bool check(LL x) { LL ans = 0; for(int i = 1; i <= n; i++) { LL l = s[i], r = min(t[i], x); if(l > r) continue; ans += (r - l) / d[i] + 1; } return (ans & 1); } int main() { int T; scanf("%d", &T); while(T--) { scanf("%d", &n); for(int i = 1; i <= n; i++) { scanf("%lld%lld%lld", &s[i], &t[i], &d[i]); } LL l = 0, r = 5e9, mid, ans = -1; while(l <= r) { mid = l + r >> 1; if(check(mid)) r = mid -1, ans = mid; else l = mid + 1; } if(ans != -1) { printf("%lld ", ans); LL cnt = 0; for(int i = 1; i <= n; i++) { if(s[i] <= ans && t[i] >= ans && (ans - s[i]) % d[i] == 0) cnt++; } printf("%lld\n", cnt); } else { puts("Poor QIN Teng:("); } } return 0; } /* */