动态规划,倒着扫一遍即可
code
#include <cstdio>
#include <cctype>
#include <cstring>
#include <algorithm>
const int N = 2e5 + 10;
int a[N], dp[N];
inline int read(){
int x = 0, op = 1; char ch = getchar();
while (!isdigit(ch)){
if (ch == '-') op = -1;ch = getchar();}
while (isdigit(ch)){
x = (x<<1)+(x<<3)+(ch^48); ch = getchar();}
return x * op;
}
inline void write(int x){
if (x < 0) putchar('-'), x = -x;
if (x > 9) write(x / 10);
putchar(x % 10 + '0');
}
void solve(){
int n = read();
memset(dp, 0, sizeof dp);
for (int i = 1; i <= n; ++i) {
a[i] = read();
}
int res = 0;
for (int i = n; i >= 1; i--) {
dp[i] = a[i];
int j = i + a[i];
if (j <= n){
dp[i] += dp[j];
}
res = std::max(res, dp[i]);
}
write(res), putchar('\n');
}
int main(){
int cases = read();
while (cases--){
solve();
}
return 0;
}