updatemax

            int l, r, val;
            cin >> l >> r >> val;
            l--;
            r--;
            for (int i = l; i <= r; ){
                if (block_start[i] && i + len - 1 <= r){
                    block[block_num[i]] += val;
                    add[block_num[i]] += val;
                    i += len;
                }
                else{
                    a[i] += val;
                    i++;
                }
            }
            int bsl = block_num[l] * len;
            block[block_num[l]] = -INF;
            for (int i = bsl; i < min(bsl + len, n); i++){
                block[block_num[l]] = max(block[block_num[l]], a[i] + add[block_num[l]]);
            }
            int bsr = block_num[r] * len;
            block[block_num[r]] = -INF;
            for (int i = bsr; i < min(bsr + len, n); i++){
                block[block_num[r]] = max(block[block_num[r]], a[i] + add[block_num[r]]);
            }