http://codeforces.com/contest/862/problem/E
二分答案
一个数与数组中的哪个数最接近：
先对数组中的数排序，然后lower_bound
1 #include <cstdio> 2 #include <cstdlib> 3 #include <cmath> 4 #include <cstring> 5 #include <time.h> 6 #include <string> 7 #include <set> 8 #include <map> 9 #include <list> 10 #include <stack> 11 #include <queue> 12 #include <vector> 13 #include <bitset> 14 #include <ext/rope> 15 #include <algorithm> 16 #include <iostream> 17 using namespace std; 18 #define ll long long 19 #define minv 1e-6 20 #define inf 1e18 21 #define pi 3.1415926536 22 #define E 2.7182818284 23 const ll mod=1e9+7;//998244353 24 const int maxn=1e5+10; 25 26 ll b[maxn],f[maxn]; 27 28 int main() 29 { 30 int n,m,q,g=0,i,l,r; 31 ll a,tot=0,sum=0,v; 32 scanf("%d%d%d",&n,&m,&q); 33 for (i=1;i<=n;i++) 34 { 35 scanf("%lld",&a); 36 if (i & 1) 37 sum+=a; 38 else 39 sum-=a; 40 } 41 for (i=1;i<=m;i++) 42 { 43 scanf("%lld",&b[i]); 44 if (i & 1) 45 tot+=b[i]; 46 else 47 tot-=b[i]; 48 if (i>=n) 49 { 50 g++; 51 if ((i-n) & 1) 52 f[g]=-tot; 53 else 54 f[g]=tot; 55 if ((i-n+1) & 1) 56 tot-=b[i-n+1]; 57 else 58 tot+=b[i-n+1]; 59 } 60 } 61 sort(f+1,f+g+1); 62 63 i=lower_bound(f+1,f+g+1,sum)-f; 64 v=inf; 65 if (i-1>=1 && i-1<=g) 66 v=min(v,abs(sum-f[i-1])); 67 if (i>=1 && i<=g) 68 v=min(v,abs(sum-f[i])); 69 if (i+1>=1 && i+1<=g) 70 v=min(v,abs(sum-f[i+1])); 71 printf("%lld ",v); 72 73 while (q--) 74 { 75 scanf("%d%d%lld",&l,&r,&a); 76 if ((r-l)%2==0) 77 { 78 if (l & 1) 79 sum+=a; 80 else 81 sum-=a; 82 } 83 84 i=lower_bound(f+1,f+g+1,sum)-f; 85 v=inf; 86 if (i-1>=1 && i-1<=g) 87 v=min(v,abs(sum-f[i-1])); 88 if (i>=1 && i<=g) 89 v=min(v,abs(sum-f[i])); 90 if (i+1>=1 && i+1<=g) 91 v=min(v,abs(sum-f[i+1])); 92 printf("%lld ",v); 93 } 94 return 0; 95 }