LA 2678 Subsequence（尺取法）

Subsequence

Time Limit: 3000ms

Memory Limit: 131072KB

This problem will be judged on UVALive. Original ID: 2678
64-bit integer IO format: %lld      Java class name: Main

Prev Submit Status Statistics Discuss Next

Font Size: + -

Type:  None Graph Theory     2-SAT     Articulation/Bridge/Biconnected Component     Cycles/Topological Sorting/Strongly Connected Component     Shortest Path         Bellman Ford         Dijkstra/Floyd Warshall     Euler Trail/Circuit     Heavy-Light Decomposition     Minimum Spanning Tree     Stable Marriage Problem     Trees     Directed Minimum Spanning Tree     Flow/Matching         Graph Matching             Bipartite Matching             Hopcroft–Karp Bipartite Matching             Weighted Bipartite Matching/Hungarian Algorithm         Flow             Max Flow/Min Cut             Min Cost Max Flow DFS-like     Backtracking with Pruning/Branch and Bound     Basic Recursion     IDA* Search     Parsing/Grammar     Breadth First Search/Depth First Search     Advanced Search Techniques         Binary Search/Bisection         Ternary Search Geometry     Basic Geometry     Computational Geometry     Convex Hull     Pick's Theorem Game Theory     Green Hackenbush/Colon Principle/Fusion Principle     Nim     Sprague-Grundy Number Matrix     Gaussian Elimination     Matrix Exponentiation Data Structures     Basic Data Structures     Binary Indexed Tree     Binary Search Tree     Hashing     Orthogonal Range Search     Range Minimum Query/Lowest Common Ancestor     Segment Tree/Interval Tree     Trie Tree     Sorting     Disjoint Set String     Aho Corasick     Knuth-Morris-Pratt     Suffix Array/Suffix Tree Math     Basic Math     Big Integer Arithmetic     Number Theory         Chinese Remainder Theorem         Extended Euclid         Inclusion/Exclusion         Modular Arithmetic     Combinatorics         Group Theory/Burnside's lemma         Counting     Probability/Expected Value Others     Tricky     Hardest     Unusual     Brute Force     Implementation     Constructive Algorithms     Two Pointer     Bitmask     Beginner     Discrete Logarithm/Shank's Baby-step Giant-step Algorithm     Greedy     Divide and Conquer Dynamic Programming                   Tag it!

[PDF Link]

A sequence of N positive integers (10 < N < 100 000), each of them less than or equal 10000, and a positive integer S (S < 100 000 000) are given. Write a program to find the minimal length of the subsequence of consecutive elements of the sequence, the sum of which is greater than or equal to S.

Input

Many test cases will be given. For each test case the program has to read the numbers N and S, separated by an interval, from the first line. The numbers of the sequence are given in the second line of the test case, separated by intervals. The input will finish with the end of file.

Output

For each the case the program has to print the result on separate line of the output file. If there isn't such a subsequence, print 0 on a line by itself.

Sample Input

10 15 5 1 3 5 10 7 4 9 2 8 5 11 1 2 3 4 5

Sample Output

2 3

Source

Regionals 2006, Europe - Southeastern

Prev Submit Status Statistics Discuss Next

模板题，找到最短的一个序列使得和大于s

#include <bits/stdc++.h>using namespace std;typedef long long ll;const int maxn = 1e5 + 10;int a[maxn];int main(){    int n,s;    while(scanf("%d%d",&n,&s)==2) {        for(int i = 1; i <= n; ++i) {            scanf("%d",a+i);        }        int ans = maxn, l = 1;        ll sum = 0;        for(int i = 1; i <= n; ++i) {            sum += a[i];            while(l <= i && sum-a[l] >= s) sum -= a[l++];            if(sum >= s) ans = min(ans,i-l+1);        }        if(ans == maxn) ans = 0;        printf("%d\n",ans);    }    return 0;}