数位DP.dp[i][j]表示i位,最高位为j的情况下总共有多少1. #include<iostream> #include<cstring> #include<cmath> #include<algorithm> #include<cstdio> #include<map> #include<queue> #include<string> #include<vector> using namesp…

简单DFS. #include<iostream> #include<cstring> #include<cmath> #include<algorithm> #include<cstdio> #include<vector> using namespace std; +; vector<int>g[maxn]; int n,m; int ans[maxn]; int root; int Deep; void dfs(in…

1049. Counting Ones (30) The task is simple: given any positive integer N, you are supposed to count the total number of 1's in the decimal form of the integers from 1 to N. For example, given N being 12, there are five 1's in 1, 10, 11, and 12. Inpu…

简单题.统计一下即可. #include<cstdio> #include<cstring> #include<cmath> #include<vector> #include<map> #include<queue> #include<stack> #include<algorithm> using namespace std; +; struct Node { int left; int right; in…

题意: 输入一个正整数N(N<=2^30),输出从1到N共有多少个数字包括1. AAAAAccepted code: #define HAVE_STRUCT_TIMESPEC #include<bits/stdc++.h> using namespace std; int main(){ ios::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL); int n; cin>>n; ; ,r=,low_bit=,yushu…

预处理出最短路再进行暴力dfs求答案会比较好.直接dfs效率太低. #include<cstdio> #include<cstring> #include<cmath> #include<vector> #include<map> #include<queue> #include<stack> #include<algorithm> using namespace std; int n,m; int st,en…

简单并查集. #include<cstdio> #include<cstring> #include<cmath> #include<vector> #include<map> #include<queue> #include<stack> #include<algorithm> using namespace std; +; int fa[maxn]; int num[maxn]; int n; vector…

暴力搜索. #include<cstdio> #include<cstring> #include<cmath> #include<vector> #include<map> #include<queue> #include<stack> #include<algorithm> using namespace std; int n,k,p,top; ]; ; ],ans_num=,ans_len; void d…

枚举一下选的位置,每次算一下就可以了. #include<cstdio> #include<cstring> #include<cmath> #include<vector> #include<map> #include<stack> #include<queue> #include<string> #include<algorithm> using namespace std; const int…

BFS求连通块.递归会爆栈. #include<cstdio> #include<cstring> #include<cmath> #include<algorithm> #include<map> #include<queue> #include<stack> #include<vector> using namespace std; int M,N,L,T; ][][]; ][][]; ][]={ {,,}…