diff --git a/Luogu/P1868/P1868.cpp b/Luogu/P1868/P1868.cpp new file mode 100644 index 00000000..8203894d --- /dev/null +++ b/Luogu/P1868/P1868.cpp @@ -0,0 +1,39 @@ +#include +#include + +using std::cin; +using std::cout; +const char endl = '\n'; + +const int N = 1.5e5 + 5, + M = 3e6 + 5; + +int n, f[M], e[M]; +int l = std::numeric_limits::max(), + r = std::numeric_limits::min(); +std::pair a[N]; +bool vis[M]; + +int main() { + std::ios::sync_with_stdio(false); + + cin >> n; + for (int i = 1, x, y; i <= n; i++) { + cin >> x >> y; + r = std::max(r, y); + e[x] = y; + vis[x] = true; + } + + for (int i = r; i; i--) { + if (vis[i]) { + f[i] = std::max(f[i + 1], f[e[i] + 1] + (e[i] - i + 1)); + } else { + f[i] = f[i + 1]; + } + } + + cout << f[1] << endl; + + return 0; +}