https://www.patest.cn/contests/pat-a-practise/1010
题目大意：
输入四个数字，a,b,c,d。
a和b是两个数字，c=1表示是第一个数字，c=2表示是第二个数字，d表示该数字是几进制
问：a和b是否能在某一进制下相等
思路：
傻逼二分...
一年没写过了，细节思考竟然差了这么多，尴尬了...
1 //看看会不会爆int!数组会不会少了一维！ 2 //取物问题一定要小心先手胜利的条件 3 #include <bits/stdc++.h> 4 using namespace std; 5 #pragma comment(linker,"/STACK:102400000,102400000") 6 #define LL long long 7 #define ALL(a) a.begin(), a.end() 8 #define pb push_back 9 #define mk make_pair 10 #define fi first 11 #define se second 12 #define haha printf("haha ") 13 const int maxn = 1e5 + 5; 14 LL val; 15 char ch1[maxn], ch2[maxn]; 16 17 LL get_int(char ch){ 18 if (ch >= '0' && ch <= '9') return 1LL * (ch - '0'); 19 return 1LL * (ch - 'a' + 10); 20 } 21 //c 1100 1 26 22 bool flag; 23 LL cal(LL x, int n){ 24 LL ans = 1; 25 26 while (n){ 27 if (n & 1) ans *= x; 28 x = x * x; 29 if (x < 0 || ans < 0) flag = false; 30 n /= 2; 31 } 32 return ans; 33 } 34 35 LL get_val(vector<LL> ve, int radix){ 36 LL sum = 0; 37 int cnt = 0; 38 for (int i = ve.size() - 1; i >= 0; i--){ 39 sum = sum + ve[i] * cal(1LL * radix, cnt); 40 cnt++; 41 } 42 if (sum < 0) flag = false; 43 return sum; 44 } 45 46 bool solve(vector<LL> b){ 47 LL lb = 0, rb = val + 1; 48 for (int i = 0; i < b.size(); i++) 49 lb = max(lb, b[i] + 1); 50 while (lb < rb){ 51 LL mid = (lb + rb) / 2; 52 flag = true; 53 LL tmp = get_val(b, mid); 54 if (!flag) { 55 rb = mid - 1; continue; 56 } 57 if (val > tmp) lb = mid + 1; 58 if (val < tmp) rb = mid - 1; 59 if (val == tmp) rb = mid; 60 } 61 if (get_val(b, lb) == val) { 62 printf("%lld ", lb); 63 return true; 64 } 65 return false; 66 } 67 68 int main(){ 69 scanf("%s%s", ch1, ch2); 70 int ty, change; 71 scanf("%d%d", &ty, &change); 72 vector<LL> a, b; 73 if (ty == 1){ 74 for (int i = 0; ch1[i] != ' '; i++) 75 a.push_back(get_int(ch1[i])); 76 for (int i = 0; ch2[i] != ' '; i++) 77 b.push_back(get_int(ch2[i])); 78 } 79 else { 80 for (int i = 0; ch2[i] != ' '; i++) 81 a.push_back(get_int(ch2[i])); 82 for (int i = 0; ch1[i] != ' '; i++) 83 b.push_back(get_int(ch1[i])); 84 } 85 val = get_val(a, change); 86 if(!solve(b)) puts("Impossible"); 87 return 0; 88 }