1 #include <cstdio>
2 #include <iostream>
3 #include <algorithm>
4 using namespace std;
5 const int maxn = 200000 + 5;
6 int a[maxn];
7 int maxsum[maxn][30];
8 int n, k;
9
10 void RMQ(int num){
11 for (int i = 1; i <= num; i++){
12 maxsum[i][0] = a[i];
13 }
14
15 for (int j = 1; j < 30; j++){
16 for (int i = 1; i <= num; i++){
17 if (i + (1 << j) - 1 <= num){
18 maxsum[i][j] = max(maxsum[i][j - 1], maxsum[i + (1 << (j - 1))][j - 1]);
19 }
20 }
21 }
22 return;
23 }
24
25 //获取[x,y]的最大值
26 int getmax(int x, int y){
27 int k1 = (int)(log((double)(y - x + 1)) / log(2.0));
28 return max(maxsum[x][k1], maxsum[y - (1 << k1) + 1][k1]);
29 }
30
31 //获取m人的最大值(m组)
32 int Find(int m){
33 int ans = 0;
34 int num = n / m;//每组num个人
35 for (int i = 0; i < m; i++){
36 ans += getmax(1 + i*num, (i + 1)*num);
37 if (ans > k)
38 return ans;
39 }
40 return ans;
41 }
42
43 int main(){
44 while (~scanf("%d%d", &n, &k)){
45 if (n == -1 && k == -1)
46 break;
47 int sum = 0;
48 bool ok_1 = false;
49 for (int i = 1; i <= n; i++){
50 scanf("%d", &a[i]);
51 if (a[i] > k){
52 ok_1 = true;
53 }
54 sum += a[i];
55 }
56 if (ok_1){
57 printf("1\n");
58 continue;
59 }
60 if (sum < k){
61 printf("-1\n");
62 continue;
63 }
64 if (sum == k){
65 printf("%d\n", k);
66 continue;
67 }
68 //初始化
69 RMQ(n);
70 bool ok = false;
71 int l = 1;
72 int r = n;
73 int ans = 0;
74 int mid, t;
75 while (l <= r){
76 mid = (l + r) / 2;
77 t = Find(mid);
78 if (t > k){
79 r = mid - 1;
80 ans = mid;
81 ok = true;
82 }
83 else{
84 l = mid + 1;
85 }
86 }
87 if (ok)
88 printf("%d\n", ans);
89 else
90 printf("-1\n");
91 }
92 //system("pause");
93 return 0;
94 }
