首页 > 代码库 > CodeForces 722C Destroying Array (并查集)
CodeForces 722C Destroying Array (并查集)
题意：给定 n 个数，然后每次破坏一个位置的数，那么剩下的连通块的和最大是多少。
析：用并查集来做，从后往前推，一开始什么也没有，如果破坏一个，那么我们就加上一个，然后判断它左右两侧是不是存在，如果存在，那么就合并起来，
然后不断最大值，因为这个最大值肯定是不递减，所以我们一直更新就好。
代码如下：
#pragma comment(linker, "/STACK:1024000000,1024000000")#include <cstdio>#include <string>#include <cstdlib>#include <cmath>#include <iostream>#include <cstring>#include <set>#include <queue>#include <algorithm>#include <vector>#include <map>#include <cctype>#include <cmath>#include <stack>//#include <tr1/unordered_map>#define freopenr freopen("in.txt", "r", stdin)#define freopenw freopen("out.txt", "w", stdout)using namespace std;//using namespace std :: tr1;typedef long long LL;typedef pair<int, int> P;const int INF = 0x3f3f3f3f;const double inf = 0x3f3f3f3f3f3f;const LL LNF = 0x3f3f3f3f3f3f;const double PI = acos(-1.0);const double eps = 1e-8;const int maxn = 1e5 + 5;const LL mod = 10000000000007;const int N = 1e6 + 5;const int dr[] = {-1, 0, 1, 0, 1, 1, -1, -1};const int dc[] = {0, 1, 0, -1, 1, -1, 1, -1};const char *Hex[] = {"0000", "0001", "0010", "0011", "0100", "0101", "0110", "0111", "1000", "1001", "1010", "1011", "1100", "1101", "1110", "1111"};inline LL gcd(LL a, LL b){ return b == 0 ? a : gcd(b, a%b); }int n, m;const int mon[] = {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};const int monn[] = {0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};inline int Min(int a, int b){ return a < b ? a : b; }inline int Max(int a, int b){ return a > b ? a : b; }inline LL Min(LL a, LL b){ return a < b ? a : b; }inline LL Max(LL a, LL b){ return a > b ? a : b; }inline bool is_in(int r, int c){ return r >= 0 && r < n && c >= 0 && c < m;}int a[maxn], b[maxn], p[maxn];bool num[maxn];vector<LL> ans;LL ran[maxn];int Find(int x) { return x == p[x] ? x : p[x] = Find(p[x]); }int main(){ while(scanf("%d", &n) == 1){ for(int i = 1; i <= n; ++i){ scanf("%d", a+i); p[i] = i; } for(int i = 1; i <= n; ++i) scanf("%d", b+i); ans.clear(); memset(num, false, sizeof num); LL cnt = 0; for(int i = n; i > 0; --i){ ans.push_back(cnt); int x = b[i]; num[x] = true; ran[x] = a[x]; if(num[x+1]){ int y = Find(x+1); p[y] = x; ran[x] += ran[y]; } if(num[x-1]){ int y = Find(x-1); p[y] = x; ran[x] += ran[y]; } cnt = Max(cnt, ran[x]); } for(int i = ans.size()-1; i >= 0; --i) printf("%I64d\n", ans[i]); } return 0;}
CodeForces 722C Destroying Array (并查集)
声明：以上内容来自用户投稿及互联网公开渠道收集整理发布，本网站不拥有所有权，未作人工编辑处理，也不承担相关法律责任，若内容有误或涉及侵权可进行投诉： 投诉/举报 工作人员会在5个工作日内联系你，一经查实，本站将立刻删除涉嫌侵权内容。