POJ3273 Monthly Expense

　　查看原题

　　边界，就是边界和思维，怎么有效的判断中间值是大了还是小了，以及准确的找到边界！一个<写成<=就前功尽弃，还特别难找到错误！

 #include <cstdio>
 #include <algorithm>
 const int maxN = ;
 int N, M;
 int A[maxN];
 using namespace std;
 int main(void) {
     while ( == scanf("%d%d", &N, &M)) {
         int u = , l = , m, sum, cnt, i;
         for (int i = ; i < N; i++) {
             scanf("%d", &A[i]);
             u += A[i];
             l = max(l, A[i]);
         }
         while (u > l) {
             m = (l+u)>>;
             sum = cnt = ;
             for (i = ; i < N; i++) {
                 sum += A[i];
                 if (sum > m) {
                     cnt++;
                     sum = A[i];
                 }
             }
             if (cnt < M) u = m;
             else l = m+;
         }
         printf("%d\n", l);
     }
 }