分类讨论。
分几种情况讨论一下即可。
#pragma comment(linker, "/STACK:1024000000,1024000000") #include<cstdio> #include<cstring> #include<cmath> #include<algorithm> #include<vector> #include<map> #include<set> #include<queue> #include<stack> #include<ctime> #include<iostream> using namespace std; typedef long long LL; const double pi=acos(-1.0),eps=1e-10; void File() { freopen("D:\in.txt","r",stdin); freopen("D:\out.txt","w",stdout); } template <class T> inline void read(T &x) { char c = getchar(); x = 0; while(!isdigit(c)) c = getchar(); while(isdigit(c)) { x = x * 10 + c - '0'; c = getchar(); } } long long A,B,C; long long get(long long a,long long b,long long c) { long long x=min(a,min(b,c)); a=a-x; b=b-x; c=c-x; if(a==0&&b==0&&c==0) return 0; if(a!=0&&b==0&&c==0) return (a-1)*2; if(a==0&&b!=0&&c==0) return (b-1)*2; if(a==0&&b==0&&c!=0) return (c-1)*2; if(a==0&&b!=0&&c!=0) { b=b-1; c=c-1; if(b>c) return b+b-c; if(b==c) return b; return c+c-b; } if(a!=0&&b==0&&c!=0) { if(a>c) return a-1+a-1-c; if(a==c) return a; return c+c-a; } if(a!=0&&b!=0&&c==0) { if(a>b) return a-1-b+a-1; if(a==b) return a-1; return b-1+b-a; } } int main() { cin>>A>>B>>C; printf("%lld ",min(get(A,B,C),min(get(B,C,A),get(C,A,B)))); return 0; }