【题解】
二分一个最大值，check一下分出来的组数是否小于等于k即可。
1 #include<cstdio> 2 #include<algorithm> 3 #define LL long long 4 #define rg register 5 #define N 200010 6 int n,k,ans,a[N]; 7 LL l,r,mid; 8 inline int read(){ 9 int k=0,f=1; char c=getchar(); 10 while(c<'0'||c>'9')c=='-'&&(f=-1),c=getchar(); 11 while('0'<=c&&c<='9')k=k*10+c-'0',c=getchar(); 12 return k*f; 13 } 14 inline bool check(){ 15 int cnt=0; LL sum=0; 16 for(rg int i=1;i<=n;i++){ 17 sum+=a[i]; 18 if(sum>mid) cnt++,sum=a[i]; 19 } 20 if(sum) cnt++; 21 //printf("%lld %d ",mid,cnt); 22 return cnt<=k; 23 } 24 int main(){ 25 n=read(); k=read(); 26 for(rg int i=1;i<=n;i++) a[i]=read(),r+=a[i]; 27 r++; l=0; 28 while(l+1<r){ 29 mid=(l+r)>>1; 30 if(check()) r=mid; else l=mid; 31 } 32 printf("%lld ",r); 33 return 0; 34 }