{"problem":{"name":"Build Stairs","description":{"content":"There are $N$ squares arranged in a row from left to right. The height of the $i$\\-th square from the left is $H_i$. For each square, you will perform either of the following operations once: *   Dec","description_type":"Markdown"},"platform":"AtCoder","limit":{"time_limit":2000,"memory_limit":262144},"difficulty":"None","is_remote":true,"is_sync":true,"sync_url":null,"sign":"abc136_c"},"statements":[{"statement_type":"Markdown","content":"There are $N$ squares arranged in a row from left to right. The height of the $i$\\-th square from the left is $H_i$.\nFor each square, you will perform either of the following operations once:\n\n*   Decrease the height of the square by $1$.\n*   Do nothing.\n\nDetermine if it is possible to perform the operations so that the heights of the squares are non-decreasing from left to right.\n\n## Constraints\n\n*   All values in input are integers.\n*   $1 \\leq N \\leq 10^5$\n*   $1 \\leq H_i \\leq 10^9$\n\n## Input\n\nInput is given from Standard Input in the following format:\n\n$N$\n$H_1$ $H_2$ $...$ $H_N$\n\n[samples]","is_translate":false,"language":"English"}],"meta":{"iden":"abc136_c","tags":[],"sample_group":[["5\n1 2 1 1 3","Yes\n\nYou can achieve the objective by decreasing the height of only the second square from the left by $1$."],["4\n1 3 2 1","No"],["5\n1 2 3 4 5","Yes"],["1\n1000000000","Yes"]],"created_at":"2026-03-03 11:01:13"}}