后缀自动机看不懂啊QAQ
放弃了还是看点更有用的东西吧,比如斜率优化DP
先水一道
#include<cstdio> #include<cstring> #include<algorithm> #define N 1000003 #define read(x) x=getint() using namespace std; typedef long long LL; inline LL getint() { LL k = 0; int fh = 1; char c = getchar(); for(; c < ‘0‘ || c > ‘9‘; c = getchar()) if (c == ‘-‘) fh = -1; for(; c >= ‘0‘ && c <= ‘9‘; c = getchar()) k = k * 10 + c - ‘0‘; return k * fh; } LL x[N], p[N], c[N], sum[N], b[N], f[N], n, q[N]; inline LL fz(int x, int y) { return f[x] + b[x] - f[y] - b[y]; } inline LL fm(int x, int y) { return sum[x] - sum[y]; } int main() { read(n); for(int i = 1; i <= n; ++i) read(x[i]), read(p[i]), read(c[i]); for(int i = 1; i <= n; ++i) sum[i] = sum[i - 1] + p[i], b[i] = b[i - 1] + p[i] * x[i]; int h = 0, t = 1, now; for(int i = 1; i <= n; ++i) { while (h < t - 1 && fz(q[h + 1], q[h]) < x[i] * fm(q[h + 1], q[h])) ++h; now = q[h]; f[i] = f[now] + (sum[i] - sum[now]) * x[i] - b[i] + b[now] + c[i]; while (h < t - 1 && fz(q[t - 1], q[t - 2]) * fm(i, q[t - 1]) > fz(i, q[t - 1]) * fm(q[t - 1], q[t - 2])) --t; q[t++] = i; } printf("%lld\n", f[n]); return 0; }
我好蒟蒻啊,省选要爆零!
时间: 2024-10-24 04:55:16