Codeforces Round #180 (Div. 2) A. Snow Footprints 贪心
題目連接：
http://www.codeforces.com/contest/298/problem/A
Description
There is a straight snowy road, divided into n blocks. The blocks are numbered from 1 to n from left to right. If one moves from the i-th block to the (i?+?1)-th block, he will leave a right footprint on the i-th block. Similarly, if one moves from the i-th block to the (i?-?1)-th block, he will leave a left footprint on the i-th block. If there already is a footprint on the i-th block, the new footprint will cover the old one.
At the beginning, there were no footprints. Then polar bear Alice starts from the s-th block, makes a sequence of moves and ends in the t-th block. It is known that Alice never moves outside of the road.
You are given the description of Alice's footprints. Your task is to find a pair of possible values of s,?t by looking at the footprints.
Input
The first line of the input contains integer n (3?≤?n?≤?1000).
The second line contains the description of the road — the string that consists of n characters. Each character will be either "." (a block without footprint), or "L" (a block with a left footprint), "R" (a block with a right footprint).
It's guaranteed that the given string contains at least one character not equal to ".". Also, the first and the last character will always be ".". It's guaranteed that a solution exists.
Output
Print two space-separated integers — the values of s and t. If there are several possible solutions you can print any of them.
Sample Input
9
..RRLL...
Sample Output
3 4
Hint
題意
給你長度為n的字符，表示這是一條路徑。
上面有很多腳印，R表示從這兒走到了右邊，L表示從這兒走到了左邊
問你根據腳印，判斷起點和終點在哪兒。
題解：
最后圖形肯定是L連成一堆，R連成一堆，起點就是開始的位置，終點就是L，R的交界處。
代碼
#include<bits/stdc++.h> using namespace std;int main() {int n;char s[5000];scanf("%d%s",&n,s);int len = strlen(s);int a,b;for(a=0;s[a]=='.';a++);for(b=a;s[a]==s[b];b++);if(s[a]=='R'){a++,b++;printf("%d %d\n",a,b);}else{printf("%d %d\n",b,a);} }轉載于:https://www.cnblogs.com/qscqesze/p/5116451.html
總結
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