#define is unsafe
Time Limit: 2000/1000 MS (Java/Others)Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 287Accepted Submission(s): 178
Problem Description
Have you used #define in C/C++ code like the code below?#include <stdio.h>#define MAX(a , b) ((a) > (b) ? (a) : (b))int main(){printf("%d\n" , MAX(2 + 3 , 4));return 0;}Run the code and get an output: 5, right?You may think it is equal to this code:#include <stdio.h>int max(a , b) {return ((a) > (b) ? (a) : (b));}int main(){printf("%d\n" , max(2 + 3 , 4));return 0;}But they aren’t.Though they do produce the same anwser , they work in two different ways.The first code, just replace the MAX(2 + 3 , 4) with ((2 + 3) > (4) ? (2 + 3) : 4), which calculates (2 + 3) twice.While the second calculates (2 + 3) first, and send the value (5 , 4) to function max(a , b) , which calculates (2 + 3) only once.What about MAX( MAX(1+2,2) , 3 ) ? Remember "replace".First replace: MAX( (1 + 2) > 2 ? (1 + 2) : 2 , 3)Second replace: ( ( ( 1 + 2 ) > 2 ? ( 1 + 2 ) : 2 ) > 3 ? ( ( 1 + 2 ) > 2 ? ( 1 + 2 ) : 2 ) : 3).The code may calculate the same expression many times like ( 1 + 2 ) above.So #define isn’t good.In this problem,I’ll give you some strings, tell me the result and how many additions(加法) are computed.
Input
The first line is an integer T(T<=40) indicating case number.The next T lines each has a string(no longer than 1000), with MAX(a,b), digits, ‘+’ only(Yes, there’re no other characters).In MAX(a,b), a and b may be a string with MAX(c,d), digits, ‘+’.See the sample and things will be clearer.
Output
For each case, output two integers in a line separated by a single space.Integers in output won’t exceed 1000000.
Sample Input
6MAX(1,0)1+MAX(1,0)MAX(2+1,3)MAX(4,2+2)MAX(1+1,2)+MAX(2,3)MAX(MAX(1+2,3),MAX(4+5+6,MAX(7+8,9)))+MAX(10,MAX(MAX(11,12),13))
Sample Output
1 02 13 14 25 228 14
Author
madfrog
Source
HDU2010省赛集训队选拔赛（校内赛）题意: 看吧!题解: 一个简单的模拟题,用递归写超简单啊啊啊啊啊啊啊!!!!!!AC代码:#include <algorithm>#include <iostream>#include <cstring>#include <cstdlib>#include <cstdio>#include <vector>#include <cmath>using namespace std;const int MAXN = 1e3 + 100;typedef long long ll;typedef unsigned long long ull;typedef pair<int,int>P;char s[MAXN];int my_find(int l,int r){int cnt = 0;for(int i = l; i < r; i++){if(s[i] == '(') cnt++;else if(s[i] == ')') cnt–;else if(s[i] == '+' && !cnt) return i;}return -1;}int my1_find(int l,int r){int cnt = 0;for(int i = l; i < r; i++){if(s[i] == '(') cnt++;else if(s[i] == ')') cnt–;else if(s[i] == ',' && !cnt) return i;}}P solve(int l,int r){int v = my_find(l,r);if(v != -1){P a = solve(l,v);P b = solve(v + 1,r);P c = make_pair(a.first + b.first,a.second + b.second + 1);return c;}if(s[l] == 'M'){int pos = my1_find(l + 4,r);P a = solve(l + 4,pos);P b = solve(pos + 1,r – 1);if(a.first > b.first)return make_pair(a.first,a.second * 2 + b.second);else return make_pair(b.first,b.second * 2 + a.second);}int cnt,res;res = cnt = 0;for(int i = l,t = 0; i <= r; i++){if(isdigit(s[i])) t = t * 10 + s[i] – '0';else{if(i < r) cnt++;res += t;t = 0;}}return make_pair(res,cnt);}int main(){int T;cin>>T;while(T–){scanf("%s",s);int len = strlen(s);P ans = solve(0,len);printf("%d %d\n",ans.first,ans.second);}return 0;}
，生命不是一场赛跑，而是一次旅行。比赛在乎终点，而旅行在乎沿途风景。
