Intervals POJ - 1201 差分約束
阿新 • • 發佈:2019-01-12
You are given n closed, integer intervals [ai, bi] and n integers c1, ..., cn.
Write a program that:
reads the number of intervals, their end points and integers c1, ..., cn from the standard input,
computes the minimal size of a set Z of integers which has at least ci common elements with interval [ai, bi], for each i=1,2,...,n,
writes the answer to the standard output.
Input The first line of the input contains an integer n (1 <= n <= 50000) -- the number of intervals. The following n lines describe the intervals. The (i+1)-th line of the input contains three integers ai, bi and ci separated by single spaces and such that 0 <= ai <= bi <= 50000 and 1 <= ci <= bi - ai+1. Output The output contains exactly one integer equal to the minimal size of set Z sharing at least ci elements with interval [ai, bi], for each i=1,2,...,n. Sample Input Sample Output
Write a program that:
reads the number of intervals, their end points and integers c1, ..., cn from the standard input,
computes the minimal size of a set Z of integers which has at least ci common elements with interval [ai, bi], for each i=1,2,...,n,
writes the answer to the standard output.
Input The first line of the input contains an integer n (1 <= n <= 50000) -- the number of intervals. The following n lines describe the intervals. The (i+1)-th line of the input contains three integers ai, bi and ci separated by single spaces and such that 0 <= ai <= bi <= 50000 and 1 <= ci <= bi - ai+1. Output The output contains exactly one integer equal to the minimal size of set Z sharing at least ci elements with interval [ai, bi], for each i=1,2,...,n. Sample Input
5 3 7 3 8 10 3 6 8 1 1 3 1 10 11 1
6
#include<iostream> #include<cstdio> #include<algorithm> #include<cstdlib> #include<cstring> #include<string> #include<cmath> #include<map> #include<set> #include<vector> #include<queue> #include<bitset> #include<ctime> #include<deque> #include<stack> #include<functional> #include<sstream> //#include<cctype> //#pragma GCC optimize(2) using namespace std; #define maxn 200005 #define inf 0x7fffffff //#define INF 1e18 #define rdint(x) scanf("%d",&x) #define rdllt(x) scanf("%lld",&x) #define rdult(x) scanf("%lu",&x) #define rdlf(x) scanf("%lf",&x) #define rdstr(x) scanf("%s",x) typedef long long ll; typedef unsigned long long ull; typedef unsigned int U; #define ms(x) memset((x),0,sizeof(x)) const long long int mod = 1e9 + 7; #define Mod 1000000000 #define sq(x) (x)*(x) #define eps 1e-3 typedef pair<int, int> pii; #define pi acos(-1.0) //const int N = 1005; #define REP(i,n) for(int i=0;i<(n);i++) typedef pair<int, int> pii; inline ll rd() { ll x = 0; char c = getchar(); bool f = false; while (!isdigit(c)) { if (c == '-') f = true; c = getchar(); } while (isdigit(c)) { x = (x << 1) + (x << 3) + (c ^ 48); c = getchar(); } return f ? -x : x; } ll gcd(ll a, ll b) { return b == 0 ? a : gcd(b, a%b); } int sqr(int x) { return x * x; } /*ll ans; ll exgcd(ll a, ll b, ll &x, ll &y) { if (!b) { x = 1; y = 0; return a; } ans = exgcd(b, a%b, x, y); ll t = x; x = y; y = t - a / b * y; return ans; } */ struct node { int u, v, w; int nxt; }edge[maxn]; int head[maxn]; int tot; int dis[maxn]; bool vis[maxn]; void addedge(int u, int v, int w) { edge[++tot].u = u; edge[tot].v = v; edge[tot].w = w; edge[tot].nxt = head[u]; head[u] = tot; } void spfa() { queue<int>q; q.push(0); vis[0] = 1; dis[0] = 0; while (!q.empty()) { int u = q.front(); q.pop(); vis[u] = 0; for (int i = head[u]; i; i = edge[i].nxt) { int v = edge[i].v; if (dis[v] < dis[u] + edge[i].w) { dis[v] = dis[u] + edge[i].w; if (!vis[v]) { q.push(v); vis[v] = 1; } } } } } int main() { //ios::sync_with_stdio(0); // int T; rdint(T); // while (T--) { ms(head); memset(dis, -0x3f, sizeof(dis)); ms(vis); tot = 0; int maxx = 0; int n; cin >> n; for (int i = 1; i <= n; i++) { int a, b, c; rdint(a); rdint(b); rdint(c); addedge(a, b + 1, c); maxx = max(maxx, b + 1); } for (int i = 1; i <= maxx; i++) { addedge(i, i - 1, -1); addedge(i - 1, i, 0); } spfa(); cout << dis[maxx] << endl; // if (T)cout << endl; // } return 0; }