CSU 1510 Happy Robot
1510: Happy Robot
Time Limit: 1 Sec Memory Limit: 128 MB
Submit: 19 Solved: 7
Description
Input
There will be at most 1000 test cases. Each case contains a command sequence with no more than 1000 characters.
Output
For each test case, print the case number, followed by minimal/maximal possible x (in this order), then the minimal/maximal possible y.
Sample Input
F?F
L??
LFFFRF
Sample Output
Case 1: 1 3 -1 1
Case 2: -1 1 0 2
Case 3: 1 1 3 3
HINT
Source
解题：dp啦，现场居然没做出来。。。笨得还可以。。
1 #include <iostream> 2 #include <cstdio> 3 #include <cstring> 4 #include <cmath> 5 #include <algorithm> 6 #include <climits> 7 #include <vector> 8 #include <queue> 9 #include <cstdlib> 10 #include <string> 11 #include <set> 12 #include <stack> 13 #define LL long long 14 #define pii pair<int,int> 15 #define INF 0x3f3f3f3f 16 using namespace std; 17 const int maxn = 1010; 18 char cmd[maxn]; 19 int dp[2][4]; 20 const int dir[4][2] = {1,0,0,-1,-1,0,0,1};//右 下 左 上 21 int mymax(int a,int b){ 22 return max(a,b); 23 } 24 int mymin(int a,int b){ 25 return min(a,b); 26 } 27 int go(int (*op)(int,int),bool flag,int x,int y){ 28 int cur = 0; 29 dp[0][0] = 0; 30 for(int i = 1; i < 4; ++i) 31 if(flag) dp[0][i] = -INF; 32 else dp[0][i] = INF; 33 for(int i = 0; cmd[i]; ++i) { 34 for(int k = 0; k < 4; ++k) dp[cur^1][k] = flag?-INF:INF; 35 if(cmd[i] == 'F' || cmd[i] == '?') { 36 dp[cur^1][0] = op(dp[cur^1][0],dp[cur][0]+x); 37 dp[cur^1][1] = op(dp[cur^1][1],dp[cur][1]-y); 38 dp[cur^1][2] = op(dp[cur^1][2],dp[cur][2]-x); 39 dp[cur^1][3] = op(dp[cur^1][3],dp[cur][3]+y); 40 } 41 if(cmd[i] == 'L' || cmd[i] == '?') { 42 dp[cur^1][0] = op(dp[cur^1][0],dp[cur][1]); 43 dp[cur^1][1] = op(dp[cur^1][1],dp[cur][2]); 44 dp[cur^1][2] = op(dp[cur^1][2],dp[cur][3]); 45 dp[cur^1][3] = op(dp[cur^1][3],dp[cur][0]); 46 } 47 if(cmd[i] == 'R' || cmd[i] == '?') { 48 dp[cur^1][0] = op(dp[cur^1][0],dp[cur][3]); 49 dp[cur^1][1] = op(dp[cur^1][1],dp[cur][0]); 50 dp[cur^1][2] = op(dp[cur^1][2],dp[cur][1]); 51 dp[cur^1][3] = op(dp[cur^1][3],dp[cur][2]); 52 } 53 cur ^= 1; 54 } 55 int ans = flag?-INF:INF; 56 for(int i = 0; i < 4; ++i) 57 ans = op(dp[cur][i],ans); 58 return ans; 59 } 60 int main() { 61 int cs = 1; 62 while(~scanf("%s",cmd)) { 63 int max_x = go(mymax,true,1,0); 64 int min_x = go(mymin,false,1,0); 65 int max_y = go(mymax,true,0,1); 66 int min_y = go(mymin,false,0,1); 67 printf("Case %d: %d %d %d %d\n",cs++,min_x,max_x,min_y,max_y); 68 } 69 return 0; 70 }